1. Heat the oil in a skillet over medium heat. Place turkey in the skillet, and cook until brown. Pour turkey into slow cooker.
2. Add the onion, peppers, tomato sauce, diced tomatoes, beans, jalapeƱos, corn, chili powder, and cumin. Stir and season with salt and pepper.
3. Cover and cook on High for 4 hours or low for 6 hours. Serve with toppings, if desired.