I am happy to see that holsters for the Nano are beginning to appear. Some I have found are, in no particular order,

Beretta Nano | PJ Holster LLC
Holsters by RGrizzle
Gun Leather, Concealment and Cowboy holsters, Azle, TX.
TT GunLeather High Quality Leather Gun Holsters
GUN LIST
Custom Concealed Ankle Gun Holsters Ammo Pack Chicago Screw Razor
Custom Holsters by Ed Buffaloe

I'm sure there are many more but those are the ones I've seen recently.

I recommend you look into the Remora No-Clip Holster. I have many of them myself and believe me it works just as advertised or I would not keep buying them. Inexpensive to boot and still has a LE, Safety Officers and Military Discount. That makes them a super bargin. Includes us retired older folks too. Just contact Alan Remora at http://www.remoraholsters.com and tell them VN Vet sent you. All I get is an Attaboy and that is all I need. These no-clip holsters are that good.

Vv

Crossbreed now has a nano holster. I have been really happy with their holster for my LCP so I thought I would try one for the nano.
MiniTuck | Crossbreed Holsters - MiniTuck

I have a Tagua. No model number but it works fine.

I picked up a Tagua PD2-200, which fits my Nano fine. It is a Black Leather Paddle Holster made for a 3 to 4 inch 1911. I paid $40 and I am very happy with it. In addition to that, I am also using a pocket holster for cargo pant pockets on shorts.

Two that work for me:

Masters OWB leather for Glock 26.
Tagua OWB leather for, I guess, Glock 26 also, but fits tight. Thanks for the links and info.

Check out what Robert Mika offers.