Nanos don't like light bullets, especially at first. Mine will stovepipe or otherwise fail to extract/ eject every once in a while with 115 grain bullets, pretty much any make. The springs are pretty strong. It seems to be a bit more reliable with 115 grain stuff now than it was at first, after it's been "broken in" a bit. I've never had any trouble with anything heavier than 115 grains.
Mine is very accurate as well. Very cool gun. The trigger's a little weird but once you get used to it the gun shoots great. I hold the trigger all the way back until the recoil cycle is over, and then let it reset. That shrank my groups considerably. I think the Nano is the best of the new breed of "micro" 9mms. It's what Glock should have been making for a while now.