I use ForScore and no, I wouldn't buy the nano, if I want matte I'll put a screen protector (there are removable ones too). I have no issues using a glossy screen, I only read music on my piano at home.
The screen protector cheaper I'm sure. Sometimes the light shines on the screen and I was wondering if this could be avoided. I'm still using a 2015 iPad for ForScore so no need to splash out big money the the latest iPad