Season the chicken breasts with the kosher salt and black pepper. Lay them in the bottom of a slow cooker. Cover the chicken with the chopped onion, celery and carrots. Pour in the chicken broth, cover the pot and cook on low for 6 to 8 hours.

When the chicken is cooked through and tender, remove the breasts from the slow cooker and shred the meat, or cut them into bite-sized pieces.

Keep the shredded chicken warm.

Turn the slow cooker to high and add the egg noodles. Cook them until they are tender, then return the shredded chicken to the pot and heat through.