Colorful Chicken Stew

1 lb boneless skinless chicken breasts, cubed
1 can 14 1/2 oz Italian diced tomatoes, undrained
2 medium potatoes, peeled and cut into 1/2 inch cubes
5 medium carrots, chopped
3 celery ribs, chopped
1 large onion, chopped
1 medium green pepper, chopped
2 cans (4oz each) mushroom stems & pieces, drained
2 low-sodium chicken bouillon cubes
1 tsp. sugar
1 tsp. chili powder
1/4 tsp. pepper
1 TBSP cornstarch
2 cups cold water

In a 5 qt. slow cooker, combine the first 12 ingredients. In a small bowl, combine cornstarch and water until smooth. Stir into chicken mixture. Cover and cook on low for 8 - 10 hours or until vegetables are tender.