Chargers Star D.J. Fluker -- I Once Ate 65 Chicken Nuggets ... And It Wasn't Enough

It's time for "Giant Man Story Time" with NFL star D.J. Fluker ... who is about to tell TMZ Sports the true story of a guy who ate 65 Chick-fil-A nuggets only to lose a contest to a man WHO ATE 80.

Fluker -- 6'5 and 339-lbs for you scoring at home -- was out in L.A. when our camera guy asked him about the most fast food he's ever eaten in one sitting.

That's when "Giant Man Story Time" began -- with Fluker telling us he once bravely entered a chicken nugget eatin' contest and downed 65 mini-birds, but it wasn't enough to win.

Bonus -- He also tells us who the biggest eater in the NFL is.