Here is a list of some of my favorites for a Nano:
Yasha Goby or High Fin Goby with Randall’s Pistol Shrimp
Pink Streaked Wrasse
Pygmy Possum Wrasse
Yellow or Randall’s Assessor
Eviota nigriventris aka Red Neon Eviota Goby
Green Banded Gobies
Clown Gobies *may nip @ sps corals*
Neon or Sharknose Gobies
Red Headed Goby
Firefish
Pearly Jawfish
Blue Spot Jawfish
Trimma Gobies
Pictus Blenny or Tail Spot Blenny
Hope this helps
I’ve included a few pics of some of my own inhabitants in my nano
Red Neon Eviota Goby
Yasha Goby (his Randall’s Pistol Shrimp bff was camera shy)
Pink Streaked Wrasse
Yellow Assessor
Randall’s Assessor