Remember, Fury -- one of the top heavyweight boxers on the planet -- says he's dead serious about trying his luck in the Octagon ... and plans to train with Conor McGregor.

Fury also said he's eyeing Stipe Miocic and Francis Ngannou and possible opponents.

So, we reached out to Francis to see if he was game -- and man, HE'S ALL IN!!!

In fact, the 6'4", 258-pound heavyweight says he'll make a 2-fight deal with Tyson -- if Fury agrees to meet him in the Octagon, he'll do a SECOND match in the boxing ring.

Ngannou tells us ... long before he became an MMA fighter, he had dreams of becoming a boxing champ -- and he believes he has the skill set to compete with a champ like Fury.

Ngannou says he's already instructed his management team to reach out to Fury to see if there's a way to make it happen ... and thinks the UFC would be on board.

We recently spoke to UFC honcho Dana White who told us he's a huge Fury fan and would love to get in business with him ... but advised Tyson to focus on boxing instead of trying to transition to MMA.

But, if there was a 2-fight deal including a boxing match, you gotta wonder if White -- who's launching a boxing promotion in 2020 -- would be more open to getting a deal done.

Ngannou has already gotten some pointers on how to fight Fury from Mike Tyson -- and Francis says Iron Mike has offered to train him if Fury accepts the fight.