Place all the soup ingredients in the Instant Pot. Secure the lid and make sure the valve is in the sealing position. Cook on high pressure, 18 minutes for frozen chicken, 15 minutes for fresh chicken. Let the Instant Pot naturally release for 10 minutes, then quick release any remaining pressure.
Remove the chicken from the Instant Pot and shred it with 2 forks (or you can do this right in the Instant Pot if you like). It should shred very easily. Return it to the Instant Pot and stir the soup to combine everything.
Serve immediately with cilantro, sour cream, cheddar cheese and taco chips for garnishes.
Soup can be stored in the refrigerator for 2-3 days, or can be frozen for 2-3 months.
You can use fresh or frozen chicken in this recipe, it just changes the cook time by a few minutes. I also have instructions for making this chicken taco soup in a slow cooker instead - you can find that recipe cited as the source.