Chestnut placed in rather large glass (8)
I believe the answer is:
schooner
'large glass' is the definition.
(type of glass)
'chestnut placed in rather' is the wordplay.
'chestnut' becomes 'ch' (I've seen this in other clues).
'placed in' is an insertion indicator (I've seen this in other clues).
'rather' becomes 'sooner' ('I'd sooner do that' means 'I'd rather do that').
'ch' going into 'sooner' is 'SCHOONER'.
(Other definitions for schooner that I've seen before include "Type of glass" , "Old sailing vessel and large glass" , "Two-masted sailing ship" , "wooden vessel" , "Two-master; a glass" .)