Hey,
Nanopi looks like a great little board. We haven’t tried it our self but from the looks of it, running the GrovePi is pretty doable on it. We’ll get one to tinker ourself shortly, till then you should definitely try to get it work and do post here about the progress or if you need any help.
We’ll more that happy to help you out to run the GrovePi on the NanoPi.