Place olive oil in a Dutch oven or soup pot over medium-high heat. Stir in onions and cook for 30 seconds. Stir in garlic. Add chicken broth and raise heat to high. Add undiluted cream of chicken soup and stir to mix well. Allow the soup to come to a boil. Add chiles and chicken. When soup returns to a boil, reduce the heat to low. Add the cream-style corn, chili powder and cumin. Stir to mix well. Remove pot from heat and stir in the milk. Serve at once, garnished with cheese, if desired.