Nuts are uneven spheres (8)
I believe the answer is:
oddballs
'nuts' is the definition.
(I've seen this before)
'uneven spheres' is the wordplay.
'uneven' becomes 'odd' (I've seen this before).
'spheres' becomes 'balls' (ball is a kind of sphere).
'odd'+'balls'='ODDBALLS'
'are' acts as a link.
(Other definitions for oddballs that I've seen before include "screwballs" , "Bold lads? (anag)" , "peculiar characters" , "Eccentric types" , "Weirdos" .)