Yasha Hasha Goby/Candy Striped Pistol Shrimp is a great Nano combination. Sexy Shrimp are also great, if in a group of at least 6. However, there are thoughts that they may pick at Zoanthids. We have a group of them, in a nano tank, along with lots of Zoanthids.
There are several other types of nano shrimp that can be very cool, such as Bumble Bee Shrimp, Anemone Shrimp, etc.
I don't think I'd recommend any anemone for a tank that small. I wouldn't even put one in our 24 gallon nano. Most anemone just get too large for the lil' tanks.
By the way, we do have a Nano forum, here on Reef Frontiers. I'd suggest posting there!!