Cocaine he was moving for nut (6)
I believe the answer is:
cashew
'for nut' is the definition.
(cashew is a kind of nut)
'cocaine he was moving' is the wordplay.
'cocaine' becomes 'C' (drugs abbreviation).
'moving' indicates anagramming the letters (letters are moved around).
'he'+'was'='hewas'
'hewas' with letters rearranged gives 'ashew'.
'c'+'ashew'='CASHEW'
(Other definitions for cashew that I've seen before include "Kidney-shaped nut of tropical tree" , "Acajou" , "Kidney shaped nut" , "Common type of nut" , "nut-tree" .)