It's a matter of: did Conor receive CTE, & how will it affect him? MMA guys are involved in many high risk behaviors outside the ring, possibly because their brains are risk-prone prior to becoming a fighter, possibly because they're risk-prone after receiving blows to the head as a fighter. Either way, think of Matt Hughes, Frank Mir, Ryan Jimmo, Gary Goodridge, Don Frye, Jon Jones....all have used less than perfect judgement outside the ring, possible signs of CTE.
So, will Conor die at age 89 instead of 90 due to fighting Nate? Probably not IMHO. More likely he will die at either 40, or 90. He will either make a big mistake due to the CTE, or he won't.
Again, correct me if I'm wrong, Sherdog medical community.