Heat olive oil in stock pot over medium-high heat. Add onion, green pepper, celery, and garlic. Cook until softened slightly.
Add beef (or chicken), corn, black beans, broth, and tomatoes to the pot. Bring to a boil and reduce heat to medium.
Stir in chipotle pepper and zucchini. Simmer 20 to 30 minutes. Taste and adjust salt.
Serve with your choice of toppings.