Chris Brown: Drops Big Chill On Royalty's Birthday Bash

Royalty's 2nd birthday party was truly fit for a baller princess.

Chris Brown and Nia Guzman's little one got the "Frozen" treatment Sunday. Royalty even made a grand entrance on a pony and chilled with Elsa, Anna and Olaf ... all with fake snow coming down.

We're told the sugary goodies alone -- including a customized 3-tier castle cake with rhinestone towers -- cost Royalty's parents a cool $10k at Sweet Serenity Desserts.

Chris couldn't attend, since he's on tour, but bragged about dropping $30k on the whole shindig. Apparently llamas and mini horses don't come cheap.