Here is the full list of all 17 NAIR achievements.
K.O. your opponent in only one hit
From low health, win at the last second
Lose online
Dodge an attack
Get your opponent down to 1 health. Then get bodied
Win a timeout by 1 hit
Win a timeout
Hit a 5 piece combo
Lose offline
Hit a combo!
End a set in a draw
Dash dance 10 times consecutively
Whiff 5 consecutive nairs
Wavedash
Shorthop
Nair
Play a game with the hitbox viewer enabled