Preheat oven to 425°F.
Make the totcho sauce:
Mix mayonnaise, ketchup and mustard together thoroughly. Store in the refrigerator until ready to serve.
Make the totchos:
Arrange Tater Tots in a single layer on a rimmed baking sheet. Bake in preheated oven until starting to turn brown, about 20–25 minutes.
Meanwhile, heat a large skillet over medium heat. Melt butter and add onion. Cook for 3 minutes. Add ground beef, season to taste with salt and pepper, and cook until no longer pink.
When Tater Tots are nice and crispy, remove from the oven and sprinkle cooked ground beef on top in an even layer.
Spoon 1 1/2 cups of your Mason Jar Cheese Sauce into a microwavable dish and heat about 2 minutes until warm.
Top your totchos with lettuce, tomatoes, pickles, and bacon bits. Pour your cheese sauce over the top, then finish it off with the prepared totcho sauce. Serve immediately (you won’t be able to wait anyway).
*Consuming raw or undercooked meats, poultry, seafood, shellfish, or eggs may increase your risk of foodborne illness.