Von Miller's setting the record straight ... he is NOT shacking up with Johnny Manziel.
The Superbowl MVP took to Instagram, saying, "Johnny's not staying with me but he is my BROTHER!" He added, "Like I've said a thousand times, I got his back no matter what!"
Miller's responding to comments Manziel made to TMZ Sports ... saying he and Von are living together while Johnny searches for a new football team.
Now he's gotta find someone else to split the utilities with.