Shoulder bag in small chalet exploded (7)
I believe the answer is:
satchel
'shoulder bag' is the definition.
(I've seen this before)
'small chalet exploded' is the wordplay.
'small' becomes 's' (abbreviation - e.g. clothes size).
'exploded' indicates anagramming the letters.
'chalet' is an anagram of 'atchel'.
's'+'atchel'='SATCHEL'
'in' acts as a link.
(Other definitions for satchel that I've seen before include "Schoolbag for children's books" , "Bag for school books" , "Bag -- latches (anag)" , "Small case with a shoulder strap" , "Get school item" .)