Formal:
* Chat ao vivo: This is the most literal translation and commonly used in formal settings.
* Bate-papo ao vivo: This is a more informal option, but still appropriate for most situations.
Informal:
* Chat online: This is a more casual option that is commonly used in online contexts.
Other options:
* Atendimento online: This is a more specific term that is often used to refer to live chat services offered by businesses.
* Conversação ao vivo: This is a more general term that can be used to refer to any type of live conversation.
Ultimately, the best way to say "live chat" in Portuguese will depend on the specific situation. If you are unsure, it is always best to err on the side of formality.