1. Preheat the Oven:
- Preheat your oven to 375°F (190°C). Grease a 9×13-inch baking dish with non-stick cooking spray.
2. Mix the Chicken Filling:
- In a large mixing bowl, combine the cooked chicken, Alfredo sauce, mozzarella cheese, half of the Parmesan cheese, peas (if using), garlic powder, onion powder, salt, and pepper. Mix until everything is evenly coated.
3. Assemble the Casserole:
- Spread the chicken mixture evenly into the prepared baking dish.
- Arrange the frozen tater tots in a single layer on top of the chicken mixture.
4. Add Cheese and Bake:
- Sprinkle the remaining Parmesan cheese evenly over the tater tots.
- Bake in the preheated oven for 35-40 minutes, or until the tater tots are golden brown and the casserole is bubbly.
5. Garnish and Serve:
- Let the casserole cool for 5 minutes, then garnish with chopped parsley, if desired. Serve hot.