Preheat your oven to 350°F (175°C).
In a large bowl, combine the shredded chicken, egg noodles, cream of chicken soup, sour cream, and garlic powder.
Add the frozen mixed vegetables to the mixture and stir until well combined.
Season the mixture with salt and pepper to taste, then transfer it to a greased 9x13 inch baking dish.
Sprinkle the shredded cheddar cheese evenly over the top.
Cover the dish with aluminum foil and bake in the preheated oven for 25 minutes.
Remove the foil and bake for an additional 15 minutes, or until the cheese is bubbly and golden brown.
Once baked, let the casserole cool for a few minutes before serving.
