1. Heat the oil in a medium pot over medium heat. Add the onion, red pepper, and garlic and cook until soft, about 5 minutes. Add the salsa, broth, tomatoes, chicken, corn, and chili powder. Bring to a boil, then reduce the heat and simmer the soup partially covered for 15 minutes. 2. Add salt and pepper to taste, lime juice if using. 3. Top with fat-free sour cream, tortilla chips, and cilantro.