Supporter upset girl, a kind of nut (6)
I believe the answer is:
brazil
'a kind of nut' is the definition.
'supporter upset girl' is the wordplay.
'supporter' becomes 'bra' (I've seen this before).
'upset' is a reversal indicator.
'girl' becomes 'liz' (**).
'liz' in reverse letter order is 'zil'.
'bra'+'zil'='BRAZIL'
(Other definitions for brazil that I've seen before include "Five-time winners of football's World Cup" , "Largest Latin-American country" , "This S American nut is large and three-sided" , "Nut (from South America?)" , "Red wood; nut; country" .)