Combine the potatoes, tomato, carrot, onion, and bay leaves in a slow cooker. Place the chicken breasts atop the vegetables. Stir the tomato sauce, chicken broth, and Italian seasoning in a bowl; pour over the chicken breasts. Add water as needed to assure the chicken is completely covered. Cook on Low for 6 hours. Remove the chicken breasts and cut into bite sized chunks and return to slow cooker. Continue cooking until the vegetables are tender, another 1 to 2 hours.