Pour the water into the pressure cooker insert and place the chicken breasts in the bottom. Sprinkle with the taco seasoning and minced garlic. Place black beans and corn on top, and pour salsa evenly over everything.
Seal the lid of the Instant Pot according to the owner's manual and cook on HIGH pressure for 10 minutes for thawed chicken breasts (or 12 minutes for frozen chicken breasts).
When the timer is done, allow the pressure to release naturally for 10 minutes, then carefully vent to release the remaining pressure (consult your owner's manual for more specific instructions).
Open the lid and use two forks to pull the chicken breasts into big chunks (remove the chicken to a plate or cutting board if that's easier). Stir all of the ingredients to combine. Taste and adjust seasonings, if desired. Scoop with a slotted spoon (or lift with tongs) and serve on flour tortillas (or over rice or quinoa) with plenty of your favorite toppings!
Notes
If you feel like your shredded chicken filling has too much liquid, simply use a slotted spoon to serve it. The extra liquid is actually helpful if you end up having leftovers, since it continues to get absorbed by the chicken once in the refrigerator.
Each chicken breast should weigh between 8 and 10 ounces. Add a few minutes of extra cooking time if using very large chicken breasts...12 total minutes for thawed or 15 minutes for frozen.
Adjust the spiciness of these Instant Pot Chicken Tacos by using medium or hot salsa instead of mild. For extra heat, you can also sprinkle in a little cayenne or (my favorite) chipotle chile pepper powder.