For nest command I do use overwriteClip(), but this adds clip from the project panel. If you have any modifications of a clip or effects added to it, this won't be translated on the added clip. Since I overwrite nest sequence, no modifications are needed.
Clipboard will be the way to go, I think.
I actually work on a small extension, that should take care of un-nesting, but that should not stop your experiments 🙂
