Cut pork fillet into thin strips. Combine spices in a large bowl. Add pork and toss well to combine. Set aside.
Heat 1 Tbsp oil in a large frying pan. Add onion and capsicum and cook over high heat for 5 minutes, stirring often until vegetables are just tender. Remove from pan.
Heat remaining oil in same frying pan and cook pork in batches over medium to high heat until well browned all over.
Return pork and vegetables to pan and cook for 2-3 minutes until pork is cooked through. Toss through lemon juice and half the coriander. Chop remaining coriander leaves and stir into sour cream with spring onions.
Heat tortillas according to packet instructions. Fill tortillas with pork mixture and top with sour cream. Roll up and serve immediately.