Just a few more hints that may help troubleshooting:
I´ve also encountered another error in my master material that took me forever to solve.
I was using a custom triplanar function I purchased that used a few vertex interpolators and also a few “pre skin” local position and local normal inputs.
Those threw errors with nanite tesselation/displacement and I had to figure out a different approach to use with displacemend for the triplanar function.
Since that is also related to skin data, maybe there is a connection to the new nanite tesselation in Unreal.
Another thing to note:
Nanite tesselation also didn´t seem to work correctly for me with raytraced shadows, so I had to disable them anyways for my project.
Gave some blotchy shadow artefacts, similar to the known raytraced shadow artefacts with nanite meshes that could be fixed with that console variable (naniteraytracemode or something).
Just throwing this in here, but might be completely unrelated.