Trim excess fat from pork butt; cut pork into 2-inch cubes and transfer to a large bowl.
Combine salt, oregano, cumin, black pepper, chile powder, and paprika in a small bowl. Rub pork cubes with spice mixture. Coat seasoned pork cubes lightly in olive oil; transfer to a pressure cooker. Cover pork cubes with orange juice, onion, and garlic.
Cover pork cubes with orange juice, onion, and garlic.
Place lid on the pressure cooker and lock; bring to full pressure over medium heat until pork is no longer pink in the center, about 60 minutes. Let pressure come down naturally, about 15 minutes.
Remove pork from the pressure cooker and shred meat.