Set your oven to 350°F (175°C). Grease a 9x13-inch baking dish and set aside.
Boil egg noodles in salted water until al dente. Drain and let cool slightly.
In a large bowl, combine cream of chicken soup, sour cream, milk, 1 cup of cheddar, garlic powder, onion powder, salt, and pepper. Stir until smooth.
Fold in shredded chicken, noodles, peas, and corn (if using) until evenly coated.
Transfer the mixture to the prepared baking dish and spread evenly.
Sprinkle with remaining cheddar. If using, mix crushed crackers or breadcrumbs with melted butter and scatter over the top.
Bake for 25–30 minutes until the top is golden and bubbly. Let sit for 5 minutes before serving.