1:29 PM PT -- Glen "Big Baby" Davis isn't crying over his lengthy prison sentence ... going to Instagram Live to crack jokes at his own expense -- but also pointing out there are a few positives that'll come out of his time behind bars.

Davis made the funnies in the video (watch for yourself and you'll know why we won't spell one out for you) ... while stating this is God's way of getting him to stop scarfing down hamburgers and Cheetos all day.

Sounds like we will be able to take the "Big" out of his nickname by the time he gets out of the slammer.

A federal judge just sentenced former NBA star Glen "Big Baby" Davis to prison time following allegations he swindled a ton of dough from the NBA's healthcare plan.

Davis, 38, was found guilty back in November 2023 of being part of an alleged scheme that defrauded the NBA's Players' Health and Benefit Welfare Plan ... and in a New York courtroom on Thursday, the former Boston Celtics champion was ordered to spend 40 months behind bars over it all.

Davis -- who had been facing a possible sentence of 20 years in prison in the case -- was also ordered to serve three years of supervised release. In addition, the judge said he must pay $80,000 in restitution as well.

Davis was not the only former hooper caught in the crosshairs of authorities in the case ... prosecutors previously accused ex-NBAers Shannon Brown, Tony Allen, Jamario Moon, Tony Wroten, Melvin Ely, Ruben Patterson and Darius Miles of wrongdoing too.

They also said they believed former first-round draft pick Terrence Williams was the mastermind behind the scheme. He was sentenced to 10 years in prison last August.