Set instant pot to pressure cook. (Use time below in notes, depending on the size of your breasts)
Cook for allotted time. Let the instant pot naturally release for 10 minutes. Press down on the venting knob. Let the rest of the pressure evacuate until the float valve drops. Carefully remove lid to remove remaining pressure. Let cool slightly. Shred with two forks.
Add shredded chicken back to pot to keep warm.
Heat tortillas in microwave, between damp paper towel, or shallow fry tortillas in hot oil until desired crispness.
8 corn tortillas
Assemble tacos with chicken, lettuce, tomato and grated cheese. Add any additional toppings you like. See suggested toppings in notes below.
Diced tomatoes, shredded lettuce, grated cheese, 1 cup cooked chicken