US president, on leaving, gets nothing (3)
I believe the answer is:
nix
'nothing' is the definition.
(nix can mean nothing)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for nix that I've seen before include "water sprite" , "Spiteful water spirit" , "Cancel" , "Watch out for" , "0" .)