Pro Skater Nyjah Huston -- Waka Flocka Birthday Party Shut Down ... TWICE!

Pro skater Nyjah Huston is rich and famous, but that didn't impress cops who shut down his 20th birthday party not once, but twice.

Nyjah threw himself a blowout birthday bash Saturday night at an industrial complex in the OC, featuring Waka Flocka.

Here's one of Nyjah's problems ... when you throw a rager, don't let a drunk chick vomit in the road, because the fire department spotted her, treated her and then determined the party was out of control, so they shut it down.

Nyiah was undeterred and decided to throw an after-party at his OC house. Neighbors complained because the noise was ear-splitting, so he was cited for disturbing the peace.

We did some checking ... cops have paid more than 20 visits to Nyjah's home and that's just in the last year or so.