In a large sauté pan over medium-high heat, add the oil and warm until shimmering. Sprinkle the pork generously with salt and add the meat to the pan. Sear the pork until a crust forms, about 5-7 minutes per side. After one side sears, rotate to sear all the sides and the ends. To cook the ends, you may need to hold the pork with tongs and keep it in place.
Add the sliced onion and bay leaf to the stainless steel insert of an Instant Pot. Transfer the pork to the insert and place it on top of the onions. Add any remaining salt and a few grindings of freshly ground pepper.
Seal the lid and turn the pressure valve to “sealing” or closed (all Instant Pots are different, you just want to make sure you’re locking in the steam). Cook on Manual/High Pressure for 1 1/2 hours. It will take about 40 minutes to come up to pressure before it starts counting down the time. When the Instant Pot finishes cooking, carefully release the steam manually and once it’s the pin on the lid has popped up, you can open the lid (follow your model’s directions to manually release the steam). Shred the pork with two forks or tongs. If the meat falls apart and shreds easily, change temperature setting to warm, and cover until ready to serve. If the meat doesn't fall apart, return it to the Instant Pot, seal the lid and pressure valve, and cook an additional 30 minutes.
To crisp the pork, place the shredded meat (not the liquid that accumulates in the pot) in a single layer on a sheetpan and broil on high on the top rack of the oven until slightly browned and caramelized on the edges of the meat, about 1 minute.
Serve with corn tortillas, cilantro, avocado, jalapeños, tomatillo salsa, pickled red onions and hot sauce.