The boxing match between the duo is scheduled for 26 August in what is being billed as the biggest fight in history.
While most would agree that McGregor could easily beat Mayweather in the octagon, which is what Tyson expected initially, he was not impressed that the "Notorious" will be fighting under boxing rules only.
"McGregor's gonna get killed," Tyson said, as quoted on BoxingScene. "I got mad because I thought they were gonna use MMA rules, against boxing. Because that's what it's all about – can the boxer beat the MMA guy?"
"So McConor [sic] put his dumb ass in a position where he's gonna get knocked out because [Mayweather] has been doing this all his life, since he was a little baby, and McConor can't kick or grab or stuff. He's not gonna stand much of a chance."
Despite seeing it as a one-sided encounter, Tyson enjoyed the recent world tour of press conferences, citing a "circus kind of atmosphere" and praising McGregor as a character.
"No way! No way! It's gonna be exciting," he added. "The whole thing's exciting because it's got a circus kind of atmosphere. But I love the fact that Conor's a character. Floyd never met a character like this."
Mayweather's last high-profile fight with Manny Pacquiao left a bad taste in fans' mouths, but with many people predicting it will be the same case on 26 August, "Money" promised that the bout will not be "dull" and that both fighters are aiming to finish each other.
However, Tyson does not see it going that way and believes it will be a disappointing encounter for the fans.
"There's no doubt it's gonna put a bad taste in people's mouths, but it's gonna happen," Tyson explained. "I never thought it was gonna happen. Then I heard about the rules and I said, 'The rules are just sucker rules for McGregor.'"
"McGregor took the biggest sucker rules in the history of boxing, of mixed fighting."