Yes, Bob Gale confirmed that he based the character on Trump. The over-the-top aesthetic of Biff's Pleasure Paradise Casino & Hotel in the alternate 1985 was specifically inspired by Trump's signature style of the 1980s. The gold-heavy decoration, the massive portraits of himself, and even the architectural style were meant to parody Trump.
I wonder why? I have been here for a couple of days and it's nice so far.
We are in the weirdest of all timelines when you can't tell if it's from The Onion or real news.