Dana White -- Pumped About Brock Lesnar's UFC Comeback ... 'It Doesn't Suck' (VIDEO)

Here's a shocker ... Dana White is FIRED UP about Brock Lesnar's return to the UFC -- telling TMZ Sports the ex-champ has been training like a beast and feels "like a million bucks."

We got White leaving the Laugh Factory on Sunset Blvd. Sunday night -- where he told us "it doesn't suck" to have a massive star like Lesnar booked for UFC 200.

However, he does have one concern about Brock.

We also asked Dana about taking a "Stockton Slap" from Nate Diaz -- and how the shot to the face essentially sealed the deal for his rematch with Conor McGregor.

One more thing ... we also talked about McGregor vs. Mayweather -- and while White once again shot it down, he did say if the two fought, it would be "punches, kicks and elbows."