Preheat the oven to 375°F. Lightly spray a 9×13-inch baking dish with cooking spray.
If you plan to make homemade cream of chicken soup: Add chicken broth to a saucepan on medium-high heat. Bring to a boil. Combine the flour, milk, and seasonings in a separate bowl. Stir until the flour is combined. Slowly add the mixture to the pot with the broth. Stir. Lower the heat to medium low and cook until the mixture thickens, about 6-10 minutes.
2 cups broth, 1 ½ cups milk, ½ cup all-purpose flour, ½ teaspoon onion powder, ½ teaspoon garlic powder
Add the chicken to the baking dish along with 1 teaspoon of garlic powder, 1 teaspoon onion powder, salt, and pepper to taste. Rub the spices into the chicken to ensure it's well seasoned.
1 ½ pounds skinless chicken breast or thighs
Add the egg noodles, vegetables, cream of chicken soup, chicken broth, garlic powder, onion powder, salt, and pepper directly to the baking dish. Stir until everything is well combined. Make sure the noodles are mostly submerged in liquid. Any noodles sticking out above the sauce can turn out hard and crunchy instead of tender.
12 oz package egg noodles, 10 oz frozen vegetables, 1 cup broth
Cover the baking dish tightly with aluminum foil. This is important. The trapped steam helps cook and soften the noodles. Bake for 30 minutes.
Remove the casserole from the oven and carefully remove the foil. Give everything a good stir, making sure to move the noodles around so they cook evenly. If the casserole looks dry or the noodles have absorbed most of the liquid, add a small splash of chicken broth or milk.
Sprinkle shredded cheese over the casserole. Cover with foil again and bake for 10 minutes.
2 cups grated cheddar cheese
Sprinkle the breadcrumbs over the top and then drizzle the butter over the breadcrumbs. Make sure the breadcrumbs are moistened, use more butter or oil if you need it. If not, the breadcrumbs will just sit on top and won't crisp. Return the casserole to the oven uncovered and bake for another 5-10 minutes, or until the noodles are tender, the sauce is creamy, the cheese is bubbly and the topping is golden. Do not overbake. If the noodles are cooked and the cheese is melted, it's safe to remove from the oven.
¼- ½ cup breadcrumbs, 2 tablespoons melted butter
Let the casserole rest for 5–10 minutes before serving. Don't worry if the sauce looks a little loose when it first comes out of the oven. The noodles will continue absorbing some of that sauce as the casserole rests.