'Chat, is this real?' is a 2022-onward Gen Z catchphrase — borrowed from livestreaming culture, where streamers address their viewer 'chat' — used to ask if something genuinely happened or to express disbelief. Said out loud or in text, it has become shorthand for 'is this actually true?'. If your teen uses it, they are referencing a recognised meme. Harmless and self-aware about the omnipresence of online life.