Pulled Pork Stuffed Sweet Potatoes

2 lbs. boneless pork loin;

4 large sweet potatoes, washed;

1 red onion, thinly sliced;

2 green onions, thinly sliced;

2 garlic cloves, minced;

½ cup beef stock;

1 tsp. chili powder;

1 tsp. paprika;

½ tsp. ground cumin;

¼ cup apple cider vinegar;

1 cup homemade BBQ sauce, plus extra for drizzling;

Sea salt and freshly ground black pepper;