Heat an electric pressure cooker on the saute mode. When hot, add half of the olive oil. Add half of the pork along with half of the salt, chili powder, black pepper, garlic powder and onion powder. Saute until the meat is very crisp and brown, about 10 minutes. Set the meat aside on a plate. Add the remaining olive oil, meat, salt, chili powder, black pepper, garlic powder and onion powder and cook until the meat is crisp and brown, another 10 minutes.
Add the first half of the meat back to the pressure cooker. Add the garlic and onions and cook, stirring, for 2 minutes. Pour in the chicken stock. Follow the manufacturer's guide for locking the lid and preparing to cook. Set to pressure cook on manual for 40 minutes.
After the pressure-cook cycle is complete, follow the manufacturer's guide for natural release. After 15 minutes, release the rest of the steam using quick release.
Remove the lid from the pressure cooker. Remove the pork and onions to a baking sheet. Shred the pork with 2 forks, pour over the barbecue sauce and toss to coat. Serve with the buns and Pickled Jalapenos and Onions.
If not serving right away, transfer to a 9-by-13-inch disposable aluminum pan, cover with foil and keep warm in the oven at 300 degrees F until ready to serve.
Pickled Jalapenos and Onions:
Put the jalapenos and red onions in a 16-ounce wide-mouth mason jar.
In a small saucepan, combine the vinegar, sugar, salt and 1 cup water. Bring to a boil, stirring until the sugar and salt are dissolved.
Pour the hot liquid over the veggies in the jar, screw on the lid and set aside. When it has cooled to room temperature, transfer the jar to the fridge to chill for a minimum of an hour, which will allow the vegetables to pickle. The pickles will last in the fridge for 3 days. Serve them on pulled pork sandwiches.