I have found some emulators for nestopia plus. They are more advanced emulators than normal nestopia, and some read other formats, which nestopia cannot.
I don’t understand programming and I don’t know how to add emulators to batocera. But if the creator is interested in contributing more emulators to nes. I will gladly leave you this link, with several nestopia plus, Undead and UE emulators, in case you want to add them. https://www.mediafire.com/folder/tvpuec5b5479b/ . I apologize for the writing, since I am translating with google.