L.A. Lakers star Steve Nash thinks he has a good reason NOT to pay child support -- if he does, he thinks his ex-wife will spoil the kids with limos and other luxuries.

Nash is locked in a legal war with Alejandra Nash over their 3 kids.  She currently lives in Arizona, where a judge handled their divorce and ruled she was not entitled to child support.  She's appealing the ruling and we now know what they're arguing over.

Steve convinced the divorce judge -- Alejandra doesn't need child support because he made her a millionaire 5 times over in the divorce settlement.  On top of that, she pulls in more than $30k a month.

For her part, Alejandra says Steve makes a million bucks more than her every month, and it's unfair he's not forced to use some of it for the benefit of their kids.

Steve is saying he's paying plenty -- 90% of medical, school and extracurricular activities, and  82% of the nanny's $2k a month salary.  He says he's worried if he pays more, she's an excessive spender who will spoil and damage the kids with crazy luxuries.

But there's more going on here.  As we previously reported ... Alejandra wants to move to L.A. but Steve is objecting.  It's really weird, because the b-baller has said he chose to go to the Lakers rather than the Knicks so he could be closer to his kids.

There's one thing for sure ... if Alejandra moved to L.A., Steve would probably get socked with a big child support bill -- that's just the way it works in California.

The L.A. Lakers and Kobe Bryant go together like peanut butter and bananas ... and the Lakers wouldn't dream of dumping him to save a few million bucks -- so says Lakers guard Steve Nash.

There's a lot of talk going 'round that the Lakers might cut Kobe after he tore his Achilles last week ... because it would save them a fortune in luxury taxes on his salary -- roughly $80 million to be exact.

But Nash doesn't believe a word of it ... telling TMZ, "Kobe is synonymous with the Lakers ... He's a strong person. He'll come back stronger than ever."

As for Nash's injury ... and whether he'll be ready for the playoffs ... you gotta watch the clip.

We finally found out why NBA superstar (and non-Jewish person) Steve Nash made an appearance at Bar Mitzvah in L.A. last weekend ... and it was all made possible thanks to one of the RICHEST men on the planet.

Turns out, the boy who became a man is 13-year-old Mike Feinberg -- and his daddy Jeff is a very wealthy person.

How wealthy, you ask? Well, Mr. Jeffrey Feinberg is a big-shot hedge fund manager who worked as an executive at Soros Fund Management -- as in, billionaire George Soros ... the wealthiest hedge fund manager in the world.

After a couple of years kicking ass and raking in billions for the hedge fund, Jeff branched off and ran his own investment company -- and it seems he did pretty well, 'cause back in 2009, he was reportedly in the hunt to buy a stake in the Brooklyn Nets.

Sources close to Feinberg tell us ... Jeff is a huge basketball fan with a TON of NBA friends -- including Mr. Nash.

Jeff's wife Stacey ain't exactly a nobody either ... she's the daughter of legendary sports agent Bob Woolf ... whose client list included Larry Bird, Doug Flutie, John Havlicek and even Larry King.

Point is ... if your dad's rich and your mother has sports connections up the wazoo ... you might have a chance to get Steve Nash at your Bar Mitzvah too. Maybe ...

When L.A. Lakers star Steve Nash joined the team, he said one of the benefits was that he could be closer to his kids ... which is why his legal fight to keep his children out of California is bizarre.

Sources connected with the couple tell TMZ ... Nash's ex-wife Alejandra wants to move the former couple's three children from AZ to L.A. We're told Nash has objected and is waging a legal war to prevent it from happening.

Our sources say Alejandra hired one of the biggest divorce lawyers in L.A., Lance Spiegel, to fight Nash in both AZ and California courts.

As for why Nash doesn't want his kids moving closer to him, we called his rep but haven't heard back.

Based on our research, one thing's for sure ... Nash will get socked for WAYYY more child support in CA than AZ.

We're told there is a gag order in place ... so no one can talk about the case.

Spiegel told TMZ, "I can't comment on the information you attribute to sources connected with TMZ."

He adds, "I confirm that I have been retained by Alejandra, that I cannot comment because of the reasons described and that Alejandra is not available for comment."

If you thought that crazy video of Steve Nash getting a road beer on an L.A. Freeway was too good to be true ... you were DEAD WRONG ... so says Keystone Light.

The footage is pretty insane ... an SUV of pumped up Lakers fans spot Nash in a yellow cab ... pull up next to the car ... pass the guy a Keystone Light ... and Nash accepts. The fans go wild.

Nash shot the video on his own cell phone ... which led many to believe it was all a premeditated viral video stunt to promote the beer.

But the honchos at Keystone insist it was as REAL as it gets ... telling TMZ, "While we can take credit for the 'Always Smooth' taste of Keystone Light, we had nothing to do with this video."

Smooth.

Marlon Wayans pissed all over Lakers fans celebrating the Steve Nash pickup by declaring the former league MVP will be nothing more than an elderly cheerleader for the purple and gold.

Just a few hours after Nash -- aka 'Messiah 2.0' -- signed his deal with the Lakers, Wayans summed up the trade for the 38-year-old point guard by saying, "Steve Nash is a dead man. He's getting back massages at half court ... getting ice packs on."

But his ultimate diss was comparing Nash to "The Sixth Man" -- a god awful 90s movie Marlon made ... but NO ONE saw.

Sorry Marlon, it's impossible for Nash to be that bad.

The MVP has landed ...

Steve Nash -- the newest member of the Los Angeles Lakers -- finally arrived in L.A. last night to sign his contract ... and the NBA superstar tells TMZ he can't wait to finish the paperwork and officially join the squad.

When we asked if he had anything to say to all the Phoenix Suns fans mourning his loss ... Nash simply replied, "It's tough ... you're always gonna disappoint somebody."

As for all the touristy stuff ... like Disneyland ... Nash says the Happiest Place on Earth will have to wait ... explaining, "I gotta get to work."

Welcome to town.

Nicki Minaj and her famously plump caboose rolled into Phoenix, AZ last night ... where she proceeded to grind the hell out of the crotch of 2-time NBA MVP Steve Nash.