Wine transforming nurse’s tea (9)
I believe the answer is:
sauternes
'wine' is the definition.
(Sauternes is an example)
'transforming nurse's tea' is the wordplay.
'transforming' indicates an anagram (I've seen this in other clues).
'nurses'+'tea'='nursestea'
'nursestea' is an anagram of 'SAUTERNES'.
(Other definitions for sauternes that I've seen before include "A sweet Bordeaux" , "Sweet white wine" , "Sweet French wine" .)