If you're looking for a pocket gun, there's a lot to think about. I'll tell you about my experience over the last 10 years in North Carolina, as a working I.T. professional. This may more may not be relevant to you.
My primary carry is a Kahr CM9. I normally carry it IWB under untucked polos or button-downs. In the summer months, when I can get away with baggy cargo shorts, I can pocket-carry it. Otherwise it's too bulky for pocket carry, and 9mm's don't come much smaller than that.
When I need to deep-conceal pocket-carry in work-suitable slacks or jeans, it's a Kel-Tec P3-AT in a DeSantis Nemesis pocket holster. If I was to buy a pocket .380 now, I'd look hard at the Ruger LCP, S&W Bodyguard .380 or even the Taurus TCP. None of those were available at the time I bought the Kel-Tec, and I haven't been convinced that any of them are better enough to justify a change from a gun that I've become familiar with over a period of several years and over 1200 rds.
IMHO the Kahr P380 is much too expensive for a micro .380, their pricing point for it makes no sense at all. The newer Diamondback and I.O Hellcat .380's seem to be unreliable crap from what I can gather. My KT has been reliable for several years, so long as I keep it clean. Any pocket-carried gun requires extra effort to keep it clean by nature.
I'm a long-time Makarov fan, my first carry gun was a Bulgarian Mak, and I carried an FEG SMC-918 for a long time and sometimes I carry it to this day. The FEG is very similar to the P64, it's a PPK-clone in 9x18, but Hungarian-made, and harder to find.
A P64 will be a more comfortable carry gun than a CZ82 due to its smaller size. The CZ is big for a 9x18, largely due to the double-stack magazine. That's not to say it's not an excellent weapon..it is, especially for the price (still not as cheap as they used to be!
) The P64 is going to be much more suitable for pocket carry, though. It's thinner, shorter and lighter. It has a 6+1 capacity as opposed to the CZ's 12+1, so you definitely have to take that into account, but those extra rounds do take up space and mass, especially in a pocket.
The Nano is of course a new design, so it has many technological advantages over the old Eastern Bloc milsurp guns, at least in theory. I've never shot a Nano, but I've heard good things. I looked at them a couple years ago when I went from 9x18 to 9x19 for primary carry, and I chose the Kahr CM9 instead. I've been very happy with it after about 2 years and about 1000 rds....of course now the Sig 938 is catching my eye.....big bucks, though.