WE'RE ABOUT TO FIND OUT BECAUSE WE SHOT TACKO FALL AT CHICK-FIL-A!

Fresh off an 18-point, 20-rebound game for the Maine Red Claws (the Boston Celtics' G-League team) ... TMZ Sports spotted the most likable guy in pro sports getting some grub at the airport in D.C.

And, since we're fascinated with all things Tacko, we had to ask the 24-year-old what the standard Chick-fil-A order is for someone of his stature.

So, make your guesses now ... 5 sandos? 8? 27? Dude's not only huge but he burns a ton of calories moving up and down the court.

Shout-out to Fall who couldn't have been nicer to our photog, and took a bunch of pics for the Chick-fil-A staffers who recognized him at the restaurant!

BONUS -- we also spoke with Tacko about being so well-received by fans in the Association ... and you'll love his reaction.