Set the Instant Pot to Sauté and add the olive oil.
Add the diced onion and cook, stirring frequently, until softened, about 3–4 minutes.
Turn off Sauté. Add the salsa, cumin, chili powder, garlic powder, salt, black pepper, and chicken broth to the pot and stir to combine.
Place the chicken breasts into the liquid, turning to coat with the sauce.
Secure the lid and set the valve to sealing. Cook on High Pressure for 10 minutes.
Allow a natural pressure release for 5 minutes, then perform a quick release for any remaining pressure.
Open the pot, transfer the chicken to a cutting board or bowl, and shred with two forks.
Toss the shredded chicken with the cooking juices, then serve in tortillas or as desired.