10:30 AM PT – Maury tells us he’s been trying to get Cardi on his show for 6 months to talk about Offset, but now he’s certain a show with CB and Nicki would be worthy of a primetime special.

Although the rivals tweeted Tuesday morning about being "all love" ... Maury ain’t buying it. As for who would come out on top in the lie detector test -- he thinks there's plenty of guilt to go around.

He also told us he and his staff security guards are prepared for the worst ... should the ladies agree to the polygraph showdown.

If Cardi B and Nicki Minaj really want THE TRUTH, one man is prepared to give them THE TRUTH ... and his name is Maury Povich.

Maury stepped squarely into the middle of hip-hop's biggest feud with an offer to hook both rappers up to a polygraph machine ... on his show, of course. We're thinking he'd have to make it a 2-hour special though, because there's a ton of beef to slice up:

-- Did Cardi stop Offset from doing the "No Flag" video with Nicki?
-- Did Nicki's pal Rah Ali really hit Cardi instead of security at the NYFW event?
-- Did Cardi block 21 Savage from doing "Krippy Kush" with Nicki?
-- Did Nicki leak Cardi's phone number after the NYFW fight?

And, that's just scratching the surface.

After Nicki dropped a ton of accusations on her "Queen Radio" show, she immediately offered to pay for a lie detector to prove she's in the right -- but as Maury put it, "Why pay for a Lie Detector Test @NICKIMINAJ ... when mine is FREE!"

For her part, Cardi fired back at Nicki with a ton of her own tea ... so, MP saw a huge opportunity and he pounced. Shoot your shot, Maury!

So, will they accept? Nicki SAYS she's down ... no word from Cardi yet.

Of course, with so much on the line, ya gotta wonder ... can they handle THE TRUTH?