In a large skillet, heat oil over medium heat. Add onion, garlic, bell peppers, celery and sweet potato. Sauté 5-7 minutes or until soft.
Add turkey, and cook until browned and crumbly, 5-7 minutes, stirring often to break up chunks.
Transfer mixture to a slow cooker. Add remaining ingredients, plus 1 cup water, 1 teaspoon salt and ½ tsp pepper.
Cover, and cook on low 6-8 hours or on high 4-5 hours.