Nothing to chatter about? Good (4)
I believe the answer is:
okay
'good' is the definition.
(thesaurus)
'nothing to chatter about?' is the wordplay.
'nothing' becomes 'o' (looks like zero - 0).
'to chatter' becomes 'yak' (synonyms).
'about?' is a reversal indicator (I've seen 'about' mean this).
'yak' in reverse letter order is 'kay'.
'o'+'kay'='OKAY'
(Other definitions for okay that I've seen before include "Correct" , "Alright" , "Yes; satisfactory" , "Agree" , "in order" .)