Turn the Instant Pot to sauté mode. Add oil or butter. Sauté garlic, ginger, carrot, and celery for 2 to 3 minutes until it smells amazing.
Add shredded chicken, corn, and chicken broth. Sprinkle in some salt and pepper. Stir gently.
Close the lid and set the seal. Cook on high pressure for 5 minutes. Do a quick release when done.
Switch to sauté mode again. Pour in milk or cream and stir. If you want thicker soup, add the cornstarch mixture and cook 2 more minutes.
Taste the soup. Add more salt or pepper if needed. You can also add a pinch of nutmeg or soy sauce for extra flavor.
Ladle into bowls and serve as is, or with bread or rice. Enjoy warm and cozy.