In a large skillet over medium heat, melt the butter and add the ground beef. Cook until browned then drain any excess grease. Stir in the Thousand Island dressing, mayonnaise, diced onion, chopped pickles, salt, pepper, garlic powder, and onion powder. Mix until fully combined.
Transfer the beef mixture to a greased 9 x 13” baking dish and spread it out evenly. Layer the sliced American Cheese evenly over the top.
Arrange the frozen tater tots evenly over the cheese layer. Place it into the center rack of the over for 40–45 minutes or until the tots are golden brown and crispy. Let it rest for 5 minutes, garnish with shredded lettuce and enjoy.