God returned in screen idol (4)
I believe the answer is:
odin
'god' is the definition.
(Norse god)
'returned in screen idol' is the wordplay.
'returned' says the letters should be written in reverse.
'in' says the answer is hidden in the clue.
'nido' is hidden within 'screen idol'.
'nido' reversed gives 'ODIN'.
(Other definitions for odin that I've seen before include "Mythological Norse deity" , "Old Scandinavian" , "Supreme god of war in Norse mythology" , "Chief god of Scandinavian myth" , "Supreme Scandinavian god - what a racket" .)