1.In a medium mixing bowl, add beer, garlic, orange juice, lime juice, oregano, cumin, salt, and pepper. In another bowl, season pork chunks on all sides with salt and pepper and mix well.
2.Click the “Saute” setting on the Instant Pot. Add oil and half of the pork, and sear turning every 45-60 seconds or until the pork is browned on all sides. Transfer pork to a separate clean plate, and repeat with the other half of the pork, searing until browned on all sides. Press “Cancel” to turn off the heat.
3.Pour in the sauce, and pork into the insert and toss briefly to combine. Close lid securely and set vent to “Sealing”. Press “Meat”, then press “Pressure” until the light on “High Pressure” lights up, then adjust the up/down arrows until time reads 30 minutes. After the timer goes off, let the pressure release naturally, about 15 minutes.
4.Carefully turn the vent to “Venting”, to release extra pressure then remove the lid. Turn on the oven broiler to High. Shred the pork with two forks.
5.Transfer pork with a slotted spoon to a large baking sheet. Spoon about a third of the leftover juices evenly on top of the pork. Then broil for 4-5 minutes, or until the edges of the pork begin browning and crisping up. Remove the sheet from the oven, then ladle a remaining third of the juices from the Instant Pot evenly over the pork, and then give it a good toss with some tongs. Broil for an additional 5 minutes to get the meat even more crispy. Then remove and ladle the final third of the juices over the pork, and toss to combine.
6.Sprinkle with cilantro, then serve immediately. You may refrigerate pork in a sealed container for up to 3 days, or freeze for up to 3 months.