Lollies of nice size (4)
I believe the answer is:
ices
'lollies' is the definition.
'of nice size' is the wordplay.
'of' indicates the answer is hidden within the clue.
'ICES' is hidden in the letters of 'nice size'.
(Other definitions for ices that I've seen before include "ecorates with frosting" , "they may be held in the summer" , "Decorates cake with sugar topping" , "Frozen sweets" , "Kills (slang) - sweets" .)