Check out Mike Tyson and UFC Hall of Famer "Sugar" Rashad Evans chopping it up right before the Jacksonville Jaguars took on the Tennessee Titans on Thursday ... clearly trading fight tips.

You can see Evans measuring Tyson -- and doing a half roll -- while asking Tyson to evaluate his moves.

Tyson coaches him up and gives him a few tips -- while playfully throwing some kicks in the mix, something he obviously couldn't do in the boxing ring.

40-year-old Evans was just inducted into the UFC HOF earlier this year -- but he's been hanging with Tyson a lot recently ... and you gotta wonder if there's another fight in his future.

What's interesting ... Tyson has said publicly he doesn't fight, train or lift weights any more because he's afraid of snapping back into that hyper-aggressive mindset that got him in trouble back in the day.

Instead, he smokes a ton of weed ... and honestly, he seems a lot more chill these days.