Preheat the oven to 350°F (175°C). Grease a 9x13 inch baking dish.
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.
Pour the mixture into the prepared baking dish and spread it evenly.
In a small bowl, combine the breadcrumbs and melted butter. Mix until the breadcrumbs are evenly coated.
Sprinkle the breadcrumb mixture over the top of the casserole.
Bake in the preheated oven for 30-35 minutes, or until the casserole is bubbly and the top is golden brown.
Remove from the oven and let it cool for 5 minutes before serving. Garnish with chopped parsley if desired.