25-year-old O'Malley was one of the UFC's hottest young stars ... but hasn't fought since March 2018 (he flunked a drug test after taking a supplement that was laced with a banned substance).

Despite the layoff, Sugar tells TMZ Sports his fighting skills -- and ridiculous support from fight fans -- haven't diminished at all ... and he's ready to kick Jose Quinonez's ass at UFC 248.

"It just feels like another fight. 2 years off is not that big of a deal."

O'Malley continued ... "I don't think anything's really changed. I don't think much has changed as far as the attention I'm getting, as far as how excited the fans are."

Snoop Dogg's one of those fans -- remember his "O'MALLEY!! O'MALLEY!!" commentary during the Contender Series? Awesome.

And, once the fighting's done Saturday night ... "Sugar" Sean says it's time to get high!

"I'm gonna take a rip, I'm gonna hang out with my circle. I don't have an after-party planned. I'm just gonna celebrate with some medicine and some good food and that's about it."

His post-fight grub of choice?

"I always crave pizza. I think a lot of fighters do for whatever reason."

Now, that's a plan.