Preheat oven to 375°F (190°C).
In a large skillet, heat olive oil over medium heat. Add diced onions and cook until soft, about 3-4 minutes. Add minced garlic and cook for 1 minute more.
Add ground beef or turkey and cook until browned and fully cooked through, breaking it up as it cooks.
Drain any excess fat, then add taco seasoning and 1/2 cup of water. Stir and let simmer for 3-5 minutes until sauce thickens.
Stir in black beans and corn. Cook for another 2 minutes until warmed through. Remove from heat.
In a 9x13 inch baking dish, spread the meat mixture evenly.
Sprinkle 1 cup of shredded cheddar cheese over the meat.
Arrange tater tots in a single layer on top.
Bake in preheated oven for 30 minutes, then remove and sprinkle the remaining 1 cup of cheese on top.
Return to oven and bake for another 5 minutes, or until cheese is melted and tater tots are golden and crispy.
Let rest for 5-10 minutes before serving. Add optional toppings as desired.