Place all ingredients in the Instant Pot. Secure the lid, making sure the vent is closed.
Using the display panel select the MANUAL function*. Use the +/- keys and program the Instant Pot for 15 minutes.
When the time is up, quick-release the pressure. Shred any remaining large pieces of chicken and return to the pot.
Meanwhile, in each serving bowl place 2/3 cup tortilla chips sprinkled with 2 tablespoons shredded cheese. Ladle hot soup over chips and cheese just before serving.
Serve with diced fresh avocado and cilantro.
Notes
*The MANUAL and PRESSURE COOK buttons are interchangeable.