Heat the vegetable oil in your pressure cooker on the sauté setting.
Sauté minced onion for 2–3 minutes until soft.
Add garlic, cumin, oregano, chili powder, and salt. Cook for about 1 minute until fragrant.
Place chicken breasts in the pot and pour salsa on top.
Close lid, set to sealing, and cook on high pressure for 10 minutes.
Let pressure release naturally, then remove lid.
Remove chicken and shred with forks.
Return shredded chicken to the pot and stir into sauce.
Cook uncovered for 5 more minutes to combine flavors.
Notes
Top with cilantro, lime, or sour cream. Store leftovers in fridge for 3–4 days or freeze. Reheat chicken separately from taco shells to avoid sogginess.