Set the Instant Pot to the sauté function. Add olive oil and diced onion. Sauté for about 3-4 minutes until the onion is translucent. Add minced garlic and cook for an additional 30 seconds until fragrant.
Add the chicken breasts to the pot. Sprinkle the taco seasoning over the chicken, then pour in the chicken broth.
Close the lid of the Instant Pot and ensure the valve is set to sealing. Select the manual or pressure cook setting and cook on high pressure for 10 minutes.
Once the cooking time is complete, allow the pressure to release naturally for 5 minutes, then carefully switch the valve to venting to release any remaining pressure.
Open the lid and shred the chicken using two forks. Stir in the black beans, corn, and salsa. Season with salt and pepper to taste.
Serve the chicken mixture in warm tortillas and top with your favorite toppings like shredded cheese, lettuce, diced tomatoes, sour cream, avocado, and cilantro.