Creating Easy Chicken Pot Pie Casserole is straightforward. Follow these steps:

1. Preheat the Oven: Begin by preheating your oven to 375°F (190°C). Grease a 9×13 inch baking dish with olive oil.
2. Mix the Filling: In a large bowl, combine cooked chicken, frozen peas and carrots, frozen corn, cream of chicken soup, milk, garlic powder, onion powder, black pepper, and dried thyme.
3. Spread the Filling: Pour the chicken mixture into the prepared baking dish, ensuring an even layer.
4. Prepare the Biscuits: Open the package of refrigerated biscuit dough. If desired, separate each biscuit and flatten slightly with your hands or a rolling pin.
5. Top the Casserole: Arrange the biscuits over the filling, slightly overlapping them as needed to cover the surface.
6. Bake the Casserole: Place the casserole in the preheated oven and bake for 25-30 minutes, or until the biscuits are golden brown and the filling is bubbling.
7. Cool Slightly: Once done, remove the casserole from the oven and let it cool for about 5 minutes to set.
8. Serve: Dish out portions and enjoy the comforting flavors of your Easy Chicken Pot Pie Casserole!

These clear and concise steps guide you in making an incredible casserole that everyone will love!