mid-15c., "talk idly, babble," short for chatter (v.). The meaning "converse familiarly" is from 1550s. The sense of "flirt with, ingratiate oneself with" (later often with up (adv.)) is from 1898. Related: Chatted; chatting.
adjective suffix, "full of or characterized by," from Old English -ig, from Proto-Germanic *-iga- (source also of Dutch, Danish, German -ig, Gothic -egs), from PIE -(i)ko-, adjectival suffix, cognate with elements in Greek -ikos, Latin -icus (see -ic). Originally added to nouns in Old English; used from 13c. with verbs, and by 15c. even with other adjectives (for example crispy). Adjectives such as hugy, vasty are artificial words that exist for the sake of poetical metrics.
<a href="https://www.etymonline.com/word/chatty">Etymology of chatty by etymonline</a>
Harper, D. (n.d.). Etymology of chatty. Online Etymology Dictionary. Retrieved $(datetime), from https://www.etymonline.com/word/chatty