Preheat your oven to 350°F (175°C). Lightly grease a 9x13 inch baking dish with cooking spray or butter.
Bring a large pot of salted water to a boil. Cook the wide egg noodles according to the package directions for al dente texture. Drain well and set aside.
In a large mixing bowl, combine the shredded chicken, chopped celery, onion, cream of chicken soup, milk, sour cream, poultry seasoning, and black pepper. Stir until the sauce is smooth and ingredients are evenly distributed.
Gently fold in the cooked egg noodles until they are well coated with the creamy chicken mixture.
Transfer the noodle mixture into the prepared baking dish, spreading it out into an even layer.
In a small bowl, mix the dry bread crumbs with the melted butter until the crumbs are moistened.
Sprinkle the buttery bread crumbs evenly over the top of the casserole.
Bake uncovered for 30 to 35 minutes, or until the casserole is bubbly around the edges and the topping is golden brown.
Let the casserole rest for 5 minutes before serving to allow the sauce to thicken slightly.