Nero's cousin, represented as an expert judge (11)
I believe the answer is:
connoisseur
'an expert judge' is the definition.
(I've seen this before)
'nero's cousin represented' is the wordplay.
'represented' is an anagram indicator.
'neros'+'cousin'='neroscousin'
'neroscousin' with letters rearranged gives 'CONNOISSEUR'.
'as' acts as a link.
(Other definitions for connoisseur that I've seen before include "discriminating judge" , "Expert judge of taste" , "Knowledgeable art-lover" .)