Preheat your oven to 400°F (200°C). While it's heating up, grab a large skillet and brown the ground beef over medium-high heat. Break it up as it cooks.
Once the beef is fully browned, drain off any excess grease. This is important so your casserole isn't oily!
Return the beef to the skillet (or transfer to a bowl if you prefer). Stir in the garlic powder, onion powder, salt, and black pepper. Give it a good mix so the flavors are distributed.
Now for the fun part – assembly! Grab a 9x13 inch baking dish. Spread the seasoned ground beef mixture evenly across the bottom.
Sprinkle the shredded cheddar cheese and shredded mozzarella cheese over the beef layer. Get it nice and covered in cheesy goodness!
Arrange the slices of American cheese over the shredded cheese layer. Just tear them or lay them flat to cover as much surface area as you can. This is where the magic melt happens!
Next, scatter the chopped dill pickles evenly over the cheese layers.
Dollop or drizzle the ketchup and mustard over the pickle layer. You can swirl it slightly if you like, but it will melt into the casserole anyway.
Finally, arrange the frozen tater tots in a single layer over the top of everything. Try to get them in a nice, even layer so they crisp up beautifully.
Pop the dish into your preheated oven. Bake for 25-30 minutes, or until the tater tots are golden brown and crispy, and the cheese is melted and bubbly around the edges.
Carefully remove the casserole from the oven. Let it sit for 5-10 minutes before serving to allow it to set up slightly.
Garnish with fresh chopped parsley if you like, and dig in!