Heat olive oil in a large pot over medium heat. Add onion and cook for 5 minutes. Add garlic, celery and chili powder, cumin and salt and cook for another minute. Add carrots and sweet potato, cook for 5-7 minutes, stirring occasionally. Add zucchini, mushrooms, tomatoes, green chilies, oregano, kidney beans and water. Bring to a boil, reduce heat to low and simmer covered for 10 minutes or until vegetables are tender and cooked through.