Preheat oven to 400F, spray a 9x13 casserole dish with cooking spray and set aside.
In a large skillet over medium heat add olive oil and saute onion until translucent will take about 3 minutes.
Add ground beef breaking it apart and cook until browned and no longer pink.
Add diced tomatoes, chili powder, cumin, sugar, tomato paste, tomato sauce, salt, pepper, beans and water.
Stir everything well to combine and continue to cook for another 5 minutes.
Pour mixture at the bottom of your baking dish topped with cheese.
Arrange tater tots on top and bake in the center of your oven for 20-25 minutes until bubbly and top is crisp and browned.
Serve topped with a dollop of sour cream, pico de Gallo and chopped green onions.