discourse vs chit-chat

discourse and chit-chat both are nouns.

Word	Noun	Adjective	Verb	Adverb
discourse	Yes	No	Yes	No
chit-chat	Yes	No	Yes	No

As verbs, chit-chat is a hyponym of discourse; that is, chit-chat is a word with a more specific, narrower meaning than discourse:

discourse (noun)	chit-chat (noun)
an extended communication (often interactive) dealing with some particular topic	light informal conversation for social occasions
extended verbal expression in speech or writing
an address of a religious nature (usually delivered during a church service)

discourse (verb)	chit-chat (verb)
talk at length and formally about a topic	talk socially without exchanging too much information
carry on a conversation
to consider or examine in speech or writing