Heat oil in a large pot over medium heat. Add onion, carrot and chile. Cook until onion is translucent and is tender, about 5 minutes.
Stir in oregano, cumin, and zucchini; cook 2 minutes.
Add tomatoes, stock, water, salt, and pepper (optional). Bring to a boil, reduce heat and simmer for 15 minutes.
Add meatballs and corn and simmer until meatballs are cooked through and hot.
Divide cooked rice between 6 serving bowls and ladle soup over top.
Makes 6 servings.