Nashorn creates new Modules using jdk.internal.module.Modules and also managed module export/read edges via Modules.addReads, Modules.addExports API.

Nashorn should use public Layer API (java.lang.reflect.Layer, .ModuleDescriptor) to create modules and use java.lang.reflect.Module addReads, addExports API from generated/loaded code of the appropriate module to manage module export/read links.