Begin by patting the pork loin roast dry with paper towels. Combine the salt, black pepper, garlic powder, onion powder, dried thyme, and paprika in a small bowl to create your spice rub.
Rub the spice mixture all over the pork loin, ensuring it's well-coated. Set aside to marinate for a few minutes while you prepare the pressure cooker.
Set your pressure cooker to 'Sauté' and add the olive oil. Once hot, sear the pork loin on all sides until it develops a golden-brown crust, about 3-4 minutes per side. Remove the pork loin and set it aside.
Add the sliced onion to the pressure cooker and sauté until translucent, about 2 minutes. Add the minced garlic and cook for an additional 30 seconds, being careful not to burn it.
Pour in the chicken broth, apple cider vinegar, and Worcestershire sauce, scraping up any browned bits from the bottom of the pot with a wooden spoon.
Place the pork loin back into the pressure cooker. Close the lid securely and set the valve to 'Sealing'.
Cook on 'High Pressure' for 50 minutes. Once the cooking time has elapsed, allow the pressure to release naturally for 10 minutes, then carefully quick-release any remaining pressure.
Carefully remove the pork loin from the pressure cooker and let it rest for 10 minutes before slicing. This will ensure the juices redistribute and keep the meat moist.
If desired, use the remaining liquid in the pressure cooker to create a sauce by setting the cooker to 'Sauté' and simmering until it thickens slightly, about 5-7 minutes.
Serve the sliced pork loin with the sauce drizzled over the top.