NICKY HILTON AND NEW HUBBY ALREADY AT EACH OTHER’S THROATS

The honeymoon is over for Nicky Hilton — just days after she tied the knot.

Paris‘ 20-year-old sister got hitched at a Las Vegas chapel to wealthy money manager Todd Meister — but stock in their marriage is already falling, say sources. Their problems burst spectacularly into the open after lunch at the Hollywood hot spot Koi when an irate Nicky blasted her 33- year-old husband for acting like a teenager.

And as photos from this week’s edition of the ENQUIRER show, the hotel heiress appeared very unhappy as she stormed away from her husband in the valet parking area.

“Nicky’s heading down the same bumpy road as Britney Spears did after her quickie wedding,” a pal told The ENQUIRER.

“And if she doesn’t lighten up real soon, Todd’s going to walk out.”

On August 25, Nicky, Todd and one of his pals had lunch at Koi — but what happened afterward left a bad taste in Todd’s mouth, says an insider.

“While they were waiting for their car, Todd innocently grabbed his buddy’s skateboard and started tooling around.

‘GROW UP!’

“From the way Nicky reacted, you’d think he’d stolen an old lady’s purse! She flipped out and started screaming, ‘Grow up! You’re making a fool of yourself and of me! ” ‘This is bull—-! You’re acting like an a——!’

“This was in front of maybe a half dozen people waiting for their cars. Poor Todd turned red. He was really embarrassed. And his pal just looked away, shaking his head.

“Todd looked speechless as Nicky huffed off toward the car, leaving him and his buddy in her wake.”

Divulged the pal: “That is not the first argument they have had since they got hitched. Shortly after their wedding, they went to Mexico for Nicky’s Maxim photo shoot — but they were more like an old bickering couple rather than newlyweds.

“Todd really loves Nicky, but he’s a kid at heart. He loves hanging out with his buddies and goofing off.

“Nicky is much more uptight. She’s not the free spirit Paris is, and now that she’s married, she’s even more intense. The next few months will be crucial.”

Hilton’s representative Elliot Mintz says, “Nicky and her husband are enjoying married life and doing just fine.” — TIM PLANT