From above, nice heater (4)
I believe the answer is:
'heater' is the definition.
(I've seen this in another clue)
'from above nice' is the wordplay.
'from' indicates a hidden word.
'OVEN' is hidden within 'above nice'.
(Other definitions for oven that I've seen before include "Kiln, perhaps" , "It''s used for baking or roasting" , "Kitchen appliance" , "kitchen fixture" , "Liquid oxygen; salmon" .)