Chuck Liddell: I Got Proof UFC Docs Will Clear Me to Kick Tito Ortiz's Ass Again

Chuck Liddell says he's got legit evidence his health ain't an issue, so if Tito Ortiz wants it like he claims, he can absolutely get it!!

The Iceman fired back at Ortiz when we got him out in Calabasas, telling TMZ Sports he'd be "shocked" if UFC doctors didn't clear him for an Octagon return ... to smash Tito for the 3rd time in his career.

Chuck's proof -- he recently set out to scale a 20,000-FOOT mountain for a YouTube Red special ... and the 48-year-old says their docs gave him a clean bill of health for the grueling climb.

Guessing their medical tests are a little different ... but Chuck told us the UFC's cleared fighters in way worse shape than him, anyway.

So, Liddell says he's praying Tito puts pen to paper ... but explains why he has real doubts Ortiz will do it.