Social media CMOS 14.209
Rule for notes
First name Surname of author (screen name), “up to 160 characters in place of title,” Social media platform, date of communication, URL.
Rule for bibliography
Surname, First name (screen name). “Up to 160 characters in place of title.” Social media platform, date of communication. URL.
In-text citation is often sufficient. For example: “LOL ammonites” (@HildaofWhitby, 1 May 680).