Mix the lime juice, soy sauce, tomato sauce, apple cider vinegar, minced garlic, chili powder, cumin, oregano, cayenne, salt, pepper, paprika, and 1 Tbsp of the avocado oil together for the marinade.
Marinate the steak in an airtight container overnight (or at least for an hour before cooking), making sure it is compeletly covered in the marinade.
When ready to cook, turn the Instant Pot on the "Sauté" feature.
Add 1 Tbsp of the avocado oil to the Instant Pot and cook the marinated steak for 2-3 minutes on each side.
Turn the "Sauté" feature off and pour in the remaining steak marinade.
Place the lid on the Instant Pot, set the pressure release valve to "Sealing" and set to "Manual" (high) pressure for 10 minutes.
Once the countdown has finished, let the Instant Pot naturally release on the "Keep Warm" setting for another 10 minutes.
Set the pressure release valve to "Venting" to release any remaining steam.
Once the float valve has dropped, open the lid.
Cut the steak into small cubes and place in corn tortillas.
Top the tacos with freshly chopped red onion, cheese, and cilantro!