Heat the oil in a 4-quart saucepan over medium-high heat. Add the onion and garlic and cook for 2 minutes, stirring occasionally.
Stir in the soup, milk and water and heat to a boil. Stir in the potatoes, zucchini and corn. Reduce the heat to medium-low. Cook for 35 minutes or until the potatoes are tender, stirring occasionally.
Stir in the chicken and parsley and cook until the mixture is hot and bubbling.