Turn on the Instant Pot and set it to sauté mode. Add the beef and sear it on all sides until browned, about 5-7 minutes. Remove the beef and set it aside.
Add the onion and garlic to the Instant Pot and sauté for 2-3 minutes until softened.
Add the tomato paste, chili powder, cumin, oregano, salt, and black pepper to the Instant Pot and stir to combine.
Pour in the beef broth, apple cider vinegar, and lime juice and stir to combine.
Return the beef to the Instant Pot and stir to coat it in the sauce.
Lock the lid in place and set the Instant Pot to pressure cook on high for 60 minutes.
Once the cooking cycle is complete, let the pressure release naturally for 15 minutes, then quick release any remaining pressure.
Remove the beef from the Instant Pot and shred it with a fork.
Strain the sauce through a fine mesh strainer and discard the solids.
Return the shredded beef to the Instant Pot and add the strained sauce back in. Stir to combine.
Turn on the Instant Pot to sauté mode and cook for an additional 5-10 minutes until the sauce has thickened slightly.
To assemble the tacos, warm the corn tortillas in a dry skillet or on a griddle. Spoon some of the beef and sauce onto each tortilla, then top with shredded cheese, chopped onion, chopped cilantro, and a squeeze of lime juice.