It would be difficult to go wrong with either... the Nano looks to be smaller, so it might be a little more interesting, recoil wise, but that's not much of an issue at this power level.
You've got me interested in the Nano.... I had looked at them, sort of in passing, and it seems I remember the slide was pretty difficult to operate... very strong spring? But I could be mistaken about that. I need to run by Cabelas and look at them again... like I need another 9....
It would be good if you could borrow/rent them both and shoot them.... that's sort of the bottom line.... how does it
feel?