Chayis may stand alone, though it is commonly followed by sir, as in: "Oh, chayis sir."
Chayis has taken on a much broader meaning, now referring to almost anything the speaker wants, making it difficult to interpret. "Chayis" is ofter seen as a difficult concept by females.
Ryan: I don't know, some chayis.
Who invited you, chayis?
Ohhh, chayis sir.