Set the Instant Pot to sauté and add the oil. When the oil is hot, add the chicken and cook for 2 to 3 minutes. Flip the chicken breasts over and add the onion and garlic. Cook for an additional 2 to 3 minutes, stirring the onion and garlic around the chicken breasts so they don't burn.

Add the tomatoes with the juice, chili powder, cumin, paprika, salt, and pepper. Lock the Instant Pot lid in place and set to Manual High Pressure for 8 minutes. When the 8 minutes is up, let the Instant Pot natural release for 10 minutes.

Open the vent and unlock the Instant Pot Lid. Remove the breasts from the Instant Pot and shred with 2 forks. You can also use a stand mixer or hand mixer to shred the chicken if you wish. Put the shredded chicken back in the Instant Pot with all of the juices. Stir until combined.

To serve, fill corn tortillas with chicken and desired toppings. Enjoy!