Preheat oven to 450 degrees. Place the tater tots onto a baking pan. Bake them for half of the full time specified on it's package. While the tots are baking take the onion and chop it into good size chunks or fine chunks depending on your preference. Take tater tots out of the oven and flip. Put back in the oven for about 3 minutes shorter then the full time it says to bake. Be sure to have the rest of the ingredients(chili, cheese and jalapeño peppers) ready so that you can put the rest of this masterpiece together when time expires. Take tots out of the oven. Now we will add the toppings... Pour the 3 cans of chili evenly over the tater tots. Next spread the onion over the chili. Now place the 12 slices of cheese evenly over the top of the chili. Top it off with just the right amount of sliced jalapeño peppers. Finally, place in the oven for the remaining 3 minutes or until the cheese is melted. Bon appétit!