Preheat the oven to 425°F. Line a baking sheet with parchment paper.
Thoroughly wash and dry the sweet potatoes. Poke them on all sides with a fork. Rub with oil and place on the baking sheet.
Bake for 45 minutes to 1 hour, or until cooked through. Check by inserting a knife to see if they are tender.
Meanwhile, heat a large skillet over medium heat. Add the beef and break it apart. Cook until browned, for about 7 to 10 minutes. Drain the grease.
Stir in the ketchup, garlic powder, onion powder, Worcestershire sauce, brown sugar, and mustard. Add ¼ cup of water to thin the sauce slightly, if needed. Bring to a boil over medium-high heat.
Cook for 8 to 10 minutes, or until thickened.
Remove the potatoes from the oven and cut them down the middle about ¾ of the way through. Mash the inside slightly with a fork.
Spoon in the sloppy joe filling until full, then sprinkle with cheese.
Place the potatoes back in the oven for 3 to 5 minutes, or until the cheese is melted.
Garnish with green onion and dollop with sour cream. Serve and enjoy!