Begin by trimming any excess fat from the pork butt and cutting the meat into 2-inch cubes. Transfer these cubes into a large mixing bowl.
In a separate small bowl, combine the salt, oregano, cumin, black pepper, chile powder, and paprika. Generously rub this spice mixture onto the pork cubes. Lightly coat the seasoned pork with olive oil before transferring it to the pressure cooker. Pour the orange juice over the pork, then add the coarsely chopped onion and diced garlic.
Secure the lid on the pressure cooker and lock it in place. Bring the cooker to full pressure over medium heat, allowing the pork to cook until it is no longer pink in the center, approximately 60 minutes. After cooking, let the pressure release naturally for about 15 minutes.
Carefully remove the pork from the pressure cooker and shred the meat, ready to be enjoyed in your favorite dishes.