chin music vs idle talk

chin music and idle talk both are nouns.

Word	Noun	Adjective	Verb	Adverb
chin music	Yes	No	No	No
idle talk	Yes	No	No	No

As nouns, chin music and idle talk are synonyms defined as:

Other synonyms of chin music include blether, prate, prattle.

chin music (noun)	idle talk (noun)
idle or foolish and irrelevant talk	idle or foolish and irrelevant talk