What is the Difference in NitroKey Qubes Image and Default Qubes

NitroPad, NitroPC
1

What sort of changes have been made to QubesOS?

I’ve seen the Nitro .img recommended as the one to install in a NitroPad.

I’m curious why.

2

The difference between OEM and official QubesOS image is only that the OEM one conveniently also installs the NitroKey App and needed dependancies, which is not included in the official release from QubesOS (although you can also manually install the package in your template afterwards)
That is the only difference I know of.