Place the 4 skinless, boneless chicken breast halves in the slow cooker.
Season the chicken with salt, pepper, and Creole seasoning to taste.
Add the 1 can of stewed tomatoes with their liquid to the slow cooker.
Stir in the 1 diced celery stalk, 1 diced green bell pepper, 3 minced garlic cloves, 1 diced onion, 1 can of drained mushrooms, and 1 seeded and chopped jalapeno pepper.
Cook the mixture on Low for 10 to 12 hours, or on High for 5 to 6 hours.