1Heat oven to 400°F. Spray 2-quart casserole with cooking spray. In 12-inch skillet, cook bacon over medium-high heat 5 to 7 minutes or until crisp; drain on paper towels. Crumble bacon; set aside.
2In same skillet, cook beef and onion over medium-high heat 5 to 7 minutes, stirring occasionally, until beef is thoroughly cooked; drain. Stir in ketchup, mustard, pickle relish, grill seasoning, pepper and 3/4 cup of the cheese. Spoon into casserole. Top with potato nuggets.
3Bake uncovered 25 minutes or until bubbly around edges and potatoes are golden brown. Sprinkle with remaining 3/4 cup cheese and the reserved crumbled bacon. Bake 5 minutes longer or until cheese is melted.