Nicky Hilton -- I Looked Hot Getting Married ... and Filthier Rich Than Ever

Nicky Hilton looked like a million bucks during her London wedding to James Rothschild ... but together they looked like a few billion.

Paris' little sister got married today in Kensington Palace -- yes, where Princess Diana lived -- walking down the aisle with her father, Richard Hilton, in a giant white gown that could fill a castle.

Like the debutante she is, Nicky married into another super wealthy family ... but this one's worth billions of dollars ... the Rothschilds have a couple more zeroes attached to their bank account balance than the Hiltons.

Paris was definitely hotter than your average bridesmaid.

Next up, Paris?