Final parts of chat show were quite sentimental (4)
I believe the answer is:
twee
'sentimental' is the definition.
(I've seen this before)
'final parts of chat show were quite' is the wordplay.
'final parts of' indicates one should take the final letters (I've seen 'final part of' mean this).
The last letters of 'chat show were quite' are 'TWEE'.
(Other definitions for twee that I've seen before include "Affected quaint" , "Affectedly sweet" , "Affectedly dainty or refined" , "rather quaint" , "Affectedly pretty" .)