Preheat your oven to 350°F (175°C).
In a large mixing bowl, combine the cooked egg noodles, shredded chicken, frozen mixed vegetables, cream of chicken soup, sour cream, garlic powder, onion powder, black pepper, and salt. Mix until well combined.
Transfer the mixture into a greased 9x13 inch baking dish. Spread it evenly.
Sprinkle the shredded cheddar cheese over the top of the casserole.
In a small bowl, mix the breadcrumbs with the melted butter until well coated. Sprinkle the breadcrumb mixture evenly over the cheese layer.
Bake in the preheated oven for 25-30 minutes, or until the casserole is bubbly and the top is golden brown.
Remove from the oven and let it cool for about 5 minutes before serving. Garnish with chopped parsley if desired.