Preheat the oven to 350°F.

If the chicken breasts have not been cooked, place the chicken into a large stock pot with enough water to fully cover them. Cook on medium-high heat until it is cooked through. Depending on the thickness of your chicken, this can cake 20 to 30 minutes. When the chicken is done, remove it from the water, and cut it into bite-sized cubes. If desired, you can reserve the water to cook the noodles for additional flavor.

Cook the noodles according to the package directions, using the same water you used to cook the chicken, if desired. Drain the noodles after they have cooked.

Place the butter in a medium pan over medium heat. When the butter has melted, add the onions, celery, and salt. Sauté until the celery is tender and the onions become translucent.

In a mixing bowl, make a creamy sauce by combining the two cans of condensed soup and the sour cream. Blend until you have a uniform mixture. Then add the sauteed onions and celery and the frozen vegetables to the bowl and mix well.

Fill a 2-quart casserole dish with the cooked noodles. Add the creamy sauce and stir to coat the noodles with the sauce.

In a small dish, combine the cracker crumbs and melted butter and mix until the cracker crumbs are coated with butter. Spoon the cracker crumbs on top of the casserole.

Bake the casserole for about 20 minutes before serving.