Corey Seager's late-game home run Tuesday night proved costly for at least one Phillies fan ... who straight up lost an entire plate of nachos because of it!
Here's the deal ... the Texas Rangers superstar was trying to claw his team back from down 3-1 against the Phils in the eighth inning at Citizens Bank Park -- when he launched a ball deep into right field.
As it came crashing down toward the stands, initially, it looked like it ricocheted off some railing ... leaving him with merely a double.