Preheat oven to 425 degrees F. Melt butter in 2-quart saucepot over medium heat. Add onion and salt and cook 3 minutes or until softened. Add flour and garlic and cook 2 minutes, stirring constantly. Gradually stir in milk and bring to a boil over medium-high heat. Reduce heat to low and simmer 3 minutes, stirring frequently, until mixture is thickened. Add 1-1/2 cups cheese and stir until melted. Arrange pasta to 2-quart baking dish. Pour sauce over pasta and stir gently until evenly coated. Evenly top with remaining cheese and Green Giant® Veggie Tots™. Bake 25 minutes or until mixture is bubbling and Green Giant® Veggie Tots™ are golden brown.