Katharine McPhee's Divorce Finalized ... 'Smash'ing Victory for Nick

Katharine McPhee's divorce has been finalized and Nicholas Cokas won the battle of when they separated ... which means he's walking away with a lot more cash.

Cokas is getting spousal support ... plus they're splitting a lot of the dough Katharine's made as a singer and actress. For instance, they're going 50-50 on income from her music rights on all songs made during their marriage ... which includes some still unreleased songs.

They've also agreed to split all income from her now canceled NBC show, "Smash."

Nick and Katharine hugely disagreed on when they separated -- she claimed it was March 2013, while he said May 2014. The final divorce docs say it was 2014 ... which is why they're splitting the "Smash" cash.

As for her current CBS show, "Scorpion" -- they're only divvying up the money from the pilot episode. Her $700k contract with Columbia/Epic Records is also getting split down the middle.

On the all-important car front -- Kat gets her 2012 Mercedes Benz M Class SUV, and Nick gets the 2013 Jeep Wrangler.