EDDIE MURPHY’s ex-wife NICOLE has blown her massive $15 million divorce settlement in just FOURYEARS – and now she’s millions of dollars in debt!

What’s more, the IRS has slapped her with five tax liens totaling $846,630, and she has put her opulent mansion up for sale.

When Nicole divorced Eddie in 2006 after 13 years of marriage, she chose to take a one-time payout from the comedian of $15 million, instead of monthly alimony.

But in a shockingly short span of time, she’s managed to lose all of it.

"Nicole made some bad investments with the fortune she got from Eddie, and now she is in serious financial straits," said a friend of the 42-year-old stunner.

Court records show that the IRS slapped Nicole with two liens for back taxes in November totaling $214,688.

That huge bill was on top of outstanding judgments against her for nearly $600,000 by a legal firm and another $60,000 demand for payment by a landscaping company. She also owes $5 million on her Los Angeles-area home.

"Nicole is overwhelmed by the mountain of debt she has piled up," added the source. Nicole, who has five children with Eddie, invested in an Internet jewelry business, but the venture quickly failed and Nicole lost much of her money.

"She is determined to dig her way out," maintained the friend.

"Eddie makes huge child support payments, which he has upped, knowing the hard time Nicole is going through.

"He also lavishes the kids with gifts and gives them anything they want or need."

Nicole is trying to sell her mansion so she and the kids can move to a more modest place. She’s also cutting back on the movie-star lifestyle she’d grown accustomed to, says the friend.

"She is hoping to get on her feet again soon."