Chop the carrots, onion, and celery.
Add 1/2 cup of butter and all the vegetables to the crockpot.
Add in the flour, chicken base, salt, and pepper.
Add in the chicken breast.
Pour 6 cups of chicken broth and 1/2 cup of milk over everything in the crockpot.
Stir it a bit and make sure the chicken is under the liquid.
Cook on low for 4-5 hours or on high for 2-3 hours.
About 20-30 minutes before serving, add in the 2 1/2 cups egg noodles and the 2 (10.5) oz cans of cream of chicken soup. Stir it around.