To prepare soup, heat the oil in a large Dutch oven over medium-high heat. Add 1 cup onion; sauté 3 minutes. Add oregano, cumin, and garlic; sauté 1 minute. Add Chicken Stock, potato, and chickpeas; bring to a boil, and cook 5 minutes. Add chicken, corn, salt, and zucchini; cook 5 minutes. Stir in tomato and cilantro; cook 2 minutes.
Ladle 1 cup soup into each of 10 bowls, and top with 1 tablespoon finely chopped onion, 1 tablespoon cilantro, 1 tablespoon sour cream, and 1 tablespoon cheese. Serve with lime wedges.