Parasite in nose GP treated right (7)
I believe the answer is:
sponger
'parasite' is the definition.
(I've seen this before)
'nose gp treated right' is the wordplay.
'treated' indicates anagramming the letters.
'right' becomes 'r' (common abbreviation).
'nose'+'gp'='nosegp'
'nosegp' is an anagram of 'sponge'.
'sponge'+'r'='SPONGER'
'in' acts as a link.
(Other definitions for sponger that I've seen before include "Freeloader" , "Leech" , "Parasite" , "One living at others' expense" , "Person who lives at another's expense" .)