Well.... I've considered both, handled one but shot neither.
Ruger vs Beretta?
American vs Italian?
I think the LC9 has the rep of smacking your hand around, but they're both what they are - up-close and personal pocket pistols.
Don't want to make anyone mad, but I think the LC9 newness is wearing off and the Nano will have more staying power (and resale value if you're so inclined) as time goes by. My impression (and impression only) is that the Nano is better built. Some people think it's a stupid name ... I like it. But you could call it your pocket Beretta. If I were you, I'd see which one felt better in your hand and then buy the Beretta .
Having shot neither...but having held both: My nod goes to the Ruger. I have large-ish hands and the LC9 fits better. It's also not nearly as "top heavy" as the Beretta Nano is. There seems to be a LOT of slide sticking "up" above the hand on the Nano.
I have shot a similarly-sized pistol, though, in the KelTec P-11. That sucker would beat you up, too.
Whichever feels better in your hand - go with that one. That's the one you're more apt to practice with.
A lot depends what fits you. I do not care for the LC9 for 2 reasons, a safety and mag disconnect. I like the Nano better. Another option you might check out the Kahr CM9.Good luck.
I have carried the LC9 for about 9 months now. I'm left handed and carry it in a Nemesis pocket holster, strong side. It rides in my jean or short's pocket just fine. I've put approximately 500 rounds through it without a malfunction. I find it to be accurate in the 7-15 yards range. I do not use the safety and only found that it engaged one time without my knowledge. I'm not sure how it happened, but I believe I probably bumped it when taking it in/out of its storage location. Now, I check it every time I place it in my pocket and have not found it engaged since that one time. I put a Hogue slip on grip on it and carry it with the pinky grip magazine in it.
I really like the LC9 and recommend it.
With all of that said, I have not handled a Nano. I've only seen one in a case. It seemed a little short in the grip for me.
My friends are going to yell at me for this, but I recently shot a Kel-Tec P3AT and loved it. Very smooth action, great hits on target while moving and shooting steel. I was impressed enough to put one in my collection in the future.
I handled the LC9 at a shop here. Seems well made. Better sights than the LCP. I'd probably disable the mag disconnect and not use the safety. Trigger pull is fairly long, but not necessarily a bad thing, imho.