Bring a large pot of water to a boil. Cook noodles in boiling water for about 8 minutes, or until done. Drain.
Preheat oven to 350 degrees F (175 degrees C). Coat a 9x13 inch pan with cooking spray.
In a saucepan, melt butter over medium heat. Cook celery and onion in butter until tender, stirring frequently. Stir in soup, milk, and cheese. Cook, stirring, until cheese melts.
In a large bowl, mix together the noodles, cheese sauce mixture, carrots, mushrooms, chicken, and salt and pepper. Spread mixture evenly into the prepared baking dish. Top with bread crumbs.
Bake in preheated oven for 30 minutes, or until hot.
