Creating Cowboy Casserole is an easy process if you follow these simple steps:

1. Preheat Oven: Preheat your oven to 350°F (175°C).
2. Cook the Beef: In a large skillet, cook the ground beef and chopped onion over medium heat until the meat is browned. Drain any excess fat.
3. Mix Ingredients: In the skillet, stir in the corn, green beans, cream of mushroom soup, cream of chicken soup, garlic powder, salt, and black pepper. Mix until well combined.
4. Add Cheese: Fold in half of the shredded cheddar cheese into the mixture.
5. Transfer to Casserole Dish: Pour the beef mixture into a greased 9×13-inch casserole dish, spreading it evenly.
6. Top with Tater Tots: Arrange the tater tots in a single layer over the beef mixture.
7. Bake: Place the casserole in the preheated oven and bake for 30-35 minutes, or until the tater tots are golden brown and crispy.
8. Add Remaining Cheese: In the last 5 minutes of baking, sprinkle the remaining cheddar cheese over the top, allowing it to melt.
9. Garnish: Remove from the oven and sprinkle with chopped green onions if desired.

These steps will guide you in creating an incredible Cowboy Casserole that will be the star of your dinner table.