Heat oil in a stockpot. Add the onions, zucchini, and peppers and sauté until tender. Add the garlic and sauté for another minute or two. Add the tomato pulp, seasonings, and stock and simmer, stirring occasionally, for about 20 minutes. Add chicken and greens if using and simmer until tender. Add lime juice and heat through.
Put a small handful of tortilla chips in the serving bowls, pour soup over the chips and top with cheese, avocado and cilantro.