How to Make It
Heat the olive oil in a large pot. Add the onion and bell pepper and cook, stirring occasionally, over moderately high heat until the onions are soft and translucent, about 5 to 7 minutes. Add the jalapeño and garlic and cook for 1 minute. Add the chili powder, cumin, cocoa, oregano, paprika, cayenne, red pepper, salt and a few turns of black pepper; cook, stirring, until fragrant, 1 to 2 minutes.
Stir in the tomatoes and the chicken broth and bring to a boil. Reduce to a simmer, add the chicken breast and cook for 20 minutes, stirring occasionally. Transfer the chicken to a cutting board and use two forks to pull it. Return it to the soup. Stir in the corn, if using.
Tortilla chips, diced avocado, sour cream, fresh cilantro, shredded Monterey jack or crumbled queso fresco