Cut pork into 3 to 4 large pieces. Heat oil in a large, heavy-based saucepan over high heat. Cook pork, turning, for 8 minutes or until browned all over. Transfer to a large plate.
Add onion and capsicums to pan and cook, stirring, for 5 minutes or until softened. Add seasoning and garlic, then cook, stirring, for 1 minute or until fragrant. Add salsa, passata and stock and bring to the boil. Return pork to pan.
Simmer, covered, for 2 hours or until pork is tender. Uncover and simmer for 1 hour or until pork is very tender and sauce has reduced. Remove pork from pan and transfer to a board. Return sauce to the boil. Boil, uncovered, for 10 minutes or until thickened. Skim off any excess fat. Season.
Meanwhile, remove and discard any excess fat from pork. Use two forks to roughly shred pork. Return pork to pan, then cook for 2 minutes or until heated through. Serve pork over rice with coriander, sour cream and lime wedges.