Add the onion and peppers and cook, stirring occasionally, over moderately high heat until the onions are soft, about 5 minutes. Add garlic and cook for 1 minute. Add the chili powder, cumin, cocoa, oregano, smoked paprika, red pepper, salt and a few turns of black pepper; cook 1 to 2 minutes or until fragrant.
Stir in the tomatoes, tomatoes with chilies, chicken stock and wild rice; bring to boil.
Add the chicken. Reduce heat and simmer until the chicken is cooked through and the rice is tender and puffy, about 40 to 45 minutes. Stir in the corn. Ladle the soup into bowls.
Garnish with fresh herbs, sour cream and crispy tortilla strips, if desired