Conor McGregor, 'I'll Be a Billionaire In 5 Years'

Conor McGregor just went off in his UFC 229 press conference -- vowing to destroy Khabib Nurmagomedov ... and claiming he'll be a billionaire by age 35!

Conor showed up almost 30 minutes late to the event in Las Vegas -- blaming crazy traffic. Khabib had left by the time McGregor showed up.

But, Conor didn't disappoint ... screaming about how much he hates Khabib, how great his whiskey tastes and how much money he expects to make.

Dana White had told us McGregor could make a Mayweather check ($100 mil) but Conor says the number will probably be closer to $50 mil.

Conor also accused Khabib's manager of being a terrorist who was pulled off a plane on Sept. 11, 2001 and detained by authorities. We're reaching to Khabib's camp for his side of the story.

Remember, Conor and Khabib HATE each other. When Conor threw that steel dolly at the bus in Brooklyn earlier this year, he was aiming for Khabib.

And, at the last press conference a few weeks ago, Conor called Khabib a "little rat, little weasel" ... "fanboy bitch" ... and "mad backwards c*nt."

Nurmagomedov promised to smash Conor's face in.

They'll finally get a chance to settle the beef once and for all on Saturday at UFC 229.

Who's ready?!