You can use a generic "coin pouch" as case for the RG Nano. IMO it is better and more realistic for carrying it around than larger, "proper" cases. Just need to be
Unbranded Cloth Wristlet Coin Purse Zip Closure Blue Green Fabric 7.5" x 4" | eBay
Bundle of 2 wallets-Shein zip around and unbranded 3-fold wallet coin purse, new | eBay
ACB Blowout Sale! Unbranded Double Trumpet Mouthpiece Pouch! Lot 121 - Austin Custom Brass Web Store
Women's Small Bifold Leather Wallet Ladies Mini Zipper Coin Purse Id Card Pocket | Fruugo US
Unbranded Womens Leather Wallet Black Multi-Section 5"x3" Zip Coin Purse Cards | eBay
Small Unbranded Eel Skin Coin Change Purse Gold Tone Kiss Lock Clasp | eBay