Fledgling's place (4)
I believe the answer is:
'fledgling's place' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for nest that I've seen before include "Accommodation for hobby, say" , "Snuggle in like bird" , "Casually thrown" , "Cosy place" , "Home of twigs, perhaps" .)