Conor and Nate have fought twice -- Nate won the first fight by strangling McGregor. Conor was the rematch in a majority decision. Both fights were phenomenal.

Now that Conor is back in the MMA biz after a 2-year break -- UFC Tonight's Karyn Bryant asked the Notorious who's next on his wish list of big fights.

McGregor said he's interested in scrapping with Anderson Silva -- saying, "It sounds interesting to me." There's clearly a mutual respect there.

But, Conor got most excited when talking about a rubber match with Nate Diaz.

"I've got that trilogy with Diaz. I will give that man that rematch. He gave me a rematch. I will give him a rematch."

What's interesting ... Conor says the 3rd fight will likely take place at 155 pounds -- 15 pounds lighter than they were in the first 2 fights.

However, Conor says he'd be open to fighting at 165 -- and creating a new division in the process, one that Nate has been lobbying for recently.

In fact, Conor says the UFC should start several more weight classes in 10-pound increments to create more champions and make weight cutting safer for the fighters.

Question is ... will Nate take a 3rd fight? Stay tuned ...