Nags outlets? About right! (6)
I believe the answer is:
horses
'nags' is the definition.
'outlets? about right' is the wordplay.
'outlets?' becomes 'hoses'.
'about' indicates putting letters inside.
'right' becomes 'r' (common abbreviation).
'hoses' going around 'r' is 'HORSES'.
(Other definitions for horses that I've seen before include "Equine animals" , "Eg, stallions" , "Equine beasts" , "Hoofed mammals (which go with 19 4)" , "Steeds" .)