Chris Brown -- Tags Up 76 Station

Chris Brown's graffiti monsters have reappeared ... right by the Sunset Strip ... on a famed gas station!

We got video of Chris tagging the wall ... and it's pretty awesome.

Norm's has a rich history of such displays from street artists like Banksy and Alec Monopoly ... and Alec wasn't shy about touting Chris' skills.

Norms 76 is iconic ... a million stars pump gas there, and Norm has a zillion stories.

Once the piece was complete, Chris left Norm's 76 with one of his friends ... bumping HIS OWN MUSIC on the way out.