Hi @cgerman
and welcome to the forum.
The bad news is, Checkmk does not have an out-of-the-box integration with Google CHat. But you already knew that.
The good news is, there Google Chat has an API, and webhooks work as well, so it shouldn’t be too hard to build something custom.
Take a look here to get started (linked to the right section): Notifications - via Email, SMS, Ticketsystems and more