In a large pot, sauté chicken in oil until cooked through. Add garlic and sauté for 1-2 minutes.
Add chicken broth; bring to boil. Reduce heat and cover. Simmer for 5 minutes.
Add half & half, cheese, corn, and green chilies. Cook and stir gently over low heat until the cheese is melted, making sure to reduce heat if you notice any sticking on the bottom of the pan. Stir in pimiento.
Serve immediately. Garnish with tortilla chips and cilantro, if desired.
If you are using cooked chicken, you only need to sauté it long enough to reheat it so you can add the garlic at the same time you add the chicken.