diff --git a/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/JsIrBackendContext.kt b/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/JsIrBackendContext.kt
index 8f167bb12e3..f9a282b1eb9 100644
--- a/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/JsIrBackendContext.kt
+++ b/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/JsIrBackendContext.kt
@@ -57,6 +57,7 @@ class JsIrBackendContext(
     val phaseConfig = PhaseConfig(jsPhases, configuration)
     override var inVerbosePhase: Boolean = false
 
+    val externalNestedClasses = mutableListOf<IrClass>()
     val packageLevelJsModules = mutableListOf<IrFile>()
     val declarationLevelJsModules = mutableListOf<IrDeclaration>()
 
diff --git a/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/MoveBodilessDeclarationsToSeparatePlace.kt b/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/MoveBodilessDeclarationsToSeparatePlace.kt
index 012f9dc8d89..71cd0f275d4 100644
--- a/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/MoveBodilessDeclarationsToSeparatePlace.kt
+++ b/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/MoveBodilessDeclarationsToSeparatePlace.kt
@@ -58,8 +58,22 @@ fun moveBodilessDeclarationsToSeparatePlace(context: JsIrBackendContext, module:
         }
     }, FqName.ROOT)
 
+    fun collectExternalClasses(container: IrDeclarationContainer, includeCurrentLevel: Boolean): List<IrClass> {
+        val externalClasses =
+            container.declarations.filterIsInstance<IrClass>().filter { it.isEffectivelyExternal() }
+
+        val nestedExternalClasses =
+            externalClasses.flatMap { collectExternalClasses(it, true) }
+
+        return if (includeCurrentLevel)
+            externalClasses + nestedExternalClasses
+        else
+            nestedExternalClasses
+    }
 
     fun lowerFile(irFile: IrFile): IrFile? {
+        context.externalNestedClasses += collectExternalClasses(irFile, includeCurrentLevel = false)
+
         if (irFile.getJsModule() != null || irFile.getJsQualifier() != null) {
             context.packageLevelJsModules.add(irFile)
             return null
diff --git a/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/transformers/irToJs/IrModuleToJsTransformer.kt b/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/transformers/irToJs/IrModuleToJsTransformer.kt
index 5efc6661f1a..77c732b15e7 100644
--- a/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/transformers/irToJs/IrModuleToJsTransformer.kt
+++ b/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/transformers/irToJs/IrModuleToJsTransformer.kt
@@ -9,14 +9,12 @@ import org.jetbrains.kotlin.config.CommonConfigurationKeys
 import org.jetbrains.kotlin.descriptors.Visibilities
 import org.jetbrains.kotlin.ir.backend.js.JsIrBackendContext
 import org.jetbrains.kotlin.ir.backend.js.ModuleType
-import org.jetbrains.kotlin.ir.backend.js.utils.JsGenerationContext
-import org.jetbrains.kotlin.ir.backend.js.utils.Namer
-import org.jetbrains.kotlin.ir.backend.js.utils.getJsModule
-import org.jetbrains.kotlin.ir.backend.js.utils.getJsQualifier
+import org.jetbrains.kotlin.ir.backend.js.utils.*
 import org.jetbrains.kotlin.ir.declarations.IrDeclarationWithVisibility
 import org.jetbrains.kotlin.ir.declarations.IrModuleFragment
 import org.jetbrains.kotlin.ir.declarations.IrSymbolOwner
 import org.jetbrains.kotlin.ir.util.isEffectivelyExternal
+import org.jetbrains.kotlin.ir.util.parentAsClass
 import org.jetbrains.kotlin.js.backend.ast.*
 import org.jetbrains.kotlin.js.config.JSConfigurationKeys
 import org.jetbrains.kotlin.utils.DFS
@@ -106,7 +104,7 @@ class IrModuleToJsTransformer(private val backendContext: JsIrBackendContext) :
             val qualifiedReference: JsNameRef
 
             if (jsModule != null) {
-                val internalName = rootFunction.scope.declareFreshName("moduleImport")
+                val internalName = rootFunction.scope.declareFreshName(sanitizeName("\$module\$$jsModule"))
                 packageLevelJsModules += JsImportedModule(jsModule, internalName, null)
 
                 qualifiedReference =
@@ -131,6 +129,19 @@ class IrModuleToJsTransformer(private val backendContext: JsIrBackendContext) :
             }
         }
 
+        for (externalClass in backendContext.externalNestedClasses) {
+            val declName = rootContext.getNameForDeclaration(externalClass)
+            val parentName = rootContext.getNameForDeclaration(externalClass.parentAsClass)
+            importStatements.add(
+                JsExpressionStatement(
+                    jsAssignment(
+                        declName.makeRef(),
+                        JsNameRef(externalClass.name.identifier, parentName.makeRef())
+                    )
+                )
+            )
+        }
+
         val importedJsModules = declarationLevelJsModules + packageLevelJsModules
         rootFunction.parameters += importedJsModules.map { JsParameter(it.internalName) }
 
diff --git a/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/utils/SimpleNameGenerator.kt b/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/utils/SimpleNameGenerator.kt
index 4acc76a1aa3..6bf496f0349 100644
--- a/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/utils/SimpleNameGenerator.kt
+++ b/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/utils/SimpleNameGenerator.kt
@@ -15,6 +15,7 @@ import org.jetbrains.kotlin.ir.types.classifierOrFail
 import org.jetbrains.kotlin.ir.util.isDynamic
 import org.jetbrains.kotlin.ir.util.isEffectivelyExternal
 import org.jetbrains.kotlin.ir.util.isInlined
+import org.jetbrains.kotlin.ir.util.parentAsClass
 import org.jetbrains.kotlin.js.backend.ast.JsName
 import org.jetbrains.kotlin.js.naming.isES5IdentifierPart
 import org.jetbrains.kotlin.js.naming.isES5IdentifierStart
@@ -107,12 +108,19 @@ class SimpleNameGenerator : NameGenerator {
 
             if (declaration.isEffectivelyExternal()) {
                 // TODO: descriptors are still used here due to the corresponding declaration doesn't have enough information yet
-                val descriptorForName = when (descriptor) {
+                val descriptorName = when (descriptor) {
                     is ConstructorDescriptor -> descriptor.constructedClass
                     is PropertyAccessorDescriptor -> descriptor.correspondingProperty
                     else -> descriptor
+                }.name
+
+                if (declaration is IrConstructor) return@getOrPut getNameForDeclaration(declaration.parentAsClass, context)
+
+                if (declaration is IrClass && declaration.parent is IrClass) {
+                    val parentName = getNameForDeclaration(declaration.parentAsClass, context).ident
+                    return@getOrPut context.currentScope.declareFreshName(parentName + "$" + descriptorName.identifier)
                 }
-                return@getOrPut context.staticContext.rootScope.declareName(descriptorForName.name.asString())
+                return@getOrPut context.staticContext.rootScope.declareName(descriptorName.identifier)
             }
 
             when (declaration) {
@@ -224,11 +232,11 @@ class SimpleNameGenerator : NameGenerator {
 
             nameDeclarator(sanitizeName(nameBuilder.toString()))
         }
-
-    private fun sanitizeName(name: String): String {
-        if (name.isEmpty()) return "_"
-
-        val first = name.first().let { if (it.isES5IdentifierStart()) it else '_' }
-        return first.toString() + name.drop(1).map { if (it.isES5IdentifierPart()) it else '_' }.joinToString("")
-    }
+}
+
+fun sanitizeName(name: String): String {
+    if (name.isEmpty()) return "_"
+
+    val first = name.first().let { if (it.isES5IdentifierStart()) it else '_' }
+    return first.toString() + name.drop(1).map { if (it.isES5IdentifierPart()) it else '_' }.joinToString("")
 }
diff --git a/js/js.translator/testData/box/inheritance/fromNestedNativeClass.kt b/js/js.translator/testData/box/inheritance/fromNestedNativeClass.kt
index d752b04e3ee..13eb4d566e5 100644
--- a/js/js.translator/testData/box/inheritance/fromNestedNativeClass.kt
+++ b/js/js.translator/testData/box/inheritance/fromNestedNativeClass.kt
@@ -1,4 +1,3 @@
-// IGNORE_BACKEND: JS_IR
 // EXPECTED_REACHABLE_NODES: 1288
 // FILE: foo.kt
 
diff --git a/js/js.translator/testData/box/jsModule/externalPackage.kt b/js/js.translator/testData/box/jsModule/externalPackage.kt
index 58c48166643..2eafb178e38 100644
--- a/js/js.translator/testData/box/jsModule/externalPackage.kt
+++ b/js/js.translator/testData/box/jsModule/externalPackage.kt
@@ -1,4 +1,3 @@
-// IGNORE_BACKEND: JS_IR
 // EXPECTED_REACHABLE_NODES: 1290
 // FILE: a.kt
 // MODULE_KIND: AMD
diff --git a/js/js.translator/testData/box/jsModule/externalPackagePlain.kt b/js/js.translator/testData/box/jsModule/externalPackagePlain.kt
index b8068f615c2..3da9b29e522 100644
--- a/js/js.translator/testData/box/jsModule/externalPackagePlain.kt
+++ b/js/js.translator/testData/box/jsModule/externalPackagePlain.kt
@@ -1,4 +1,3 @@
-// IGNORE_BACKEND: JS_IR
 // EXPECTED_REACHABLE_NODES: 1289
 // FILE: a.kt
 @file:JsModule("lib")
diff --git a/js/js.translator/testData/box/jsName/inheritFromRenamedNativeClass.kt b/js/js.translator/testData/box/jsName/inheritFromRenamedNativeClass.kt
index 3a572655f65..bb889e5df56 100644
--- a/js/js.translator/testData/box/jsName/inheritFromRenamedNativeClass.kt
+++ b/js/js.translator/testData/box/jsName/inheritFromRenamedNativeClass.kt
@@ -1,4 +1,3 @@
-// IGNORE_BACKEND: JS_IR
 // EXPECTED_REACHABLE_NODES: 1288
 // FILE: main.kt
 
diff --git a/js/js.translator/testData/box/jsName/inheritFromRenamedNativeClassMultimodule.kt b/js/js.translator/testData/box/jsName/inheritFromRenamedNativeClassMultimodule.kt
index 81e384010e8..a5d3a361e38 100644
--- a/js/js.translator/testData/box/jsName/inheritFromRenamedNativeClassMultimodule.kt
+++ b/js/js.translator/testData/box/jsName/inheritFromRenamedNativeClassMultimodule.kt
@@ -1,4 +1,3 @@
-// IGNORE_BACKEND: JS_IR
 // EXPECTED_REACHABLE_NODES: 1288
 // MODULE: module1
 // FILE: module1.kt
diff --git a/js/js.translator/testData/box/jsQualifier/classes.kt b/js/js.translator/testData/box/jsQualifier/classes.kt
index df97f87c8f6..c9e7040da14 100644
--- a/js/js.translator/testData/box/jsQualifier/classes.kt
+++ b/js/js.translator/testData/box/jsQualifier/classes.kt
@@ -1,4 +1,3 @@
-// IGNORE_BACKEND: JS_IR
 // EXPECTED_REACHABLE_NODES: 1282
 // MODULE: lib
 // FILE: lib.kt
diff --git a/js/js.translator/testData/box/native/useClassFromInlineFun.kt b/js/js.translator/testData/box/native/useClassFromInlineFun.kt
index 3523ba82ded..c491f21536d 100644
--- a/js/js.translator/testData/box/native/useClassFromInlineFun.kt
+++ b/js/js.translator/testData/box/native/useClassFromInlineFun.kt
@@ -1,4 +1,3 @@
-// IGNORE_BACKEND: JS_IR
 // EXPECTED_REACHABLE_NODES: 1282
 // FILE: main.kt
 
diff --git a/js/js.translator/testData/box/nestedTypes/outerNative.kt b/js/js.translator/testData/box/nestedTypes/outerNative.kt
index a3f163146fe..77d02c1df0c 100644
--- a/js/js.translator/testData/box/nestedTypes/outerNative.kt
+++ b/js/js.translator/testData/box/nestedTypes/outerNative.kt
@@ -1,4 +1,3 @@
-// IGNORE_BACKEND: JS_IR
 // EXPECTED_REACHABLE_NODES: 1281
 package foo