Start by boiling water in a large pot and cooking the egg noodles until they are al dente. They will soften but should not be mushy. Keep an eye on the clock as overcooked noodles can ruin the dish.
In a separate bowl, stir together the cream of chicken soup and milk until it is smooth and creamy. You will know it is ready when you see no clumps. This sauce binds everything together.
In a large mixing bowl, add the cooked chicken, frozen vegetables, garlic powder, onion powder, salt, and pepper. Give it a good stir to coat everything evenly.
Pour the creamy mixture over the chicken and veggies, mixing everything until it is well coated.
Spray your baking dish with cooking spray to prevent sticking, ensuring the whole bottom is covered.
Pour the noodle mixture into the greased baking dish. Top it with shredded cheddar cheese, allowing it to melt and create a crust.
Pop the casserole in the oven until it is bubbling and golden.