Heat oven to 425°F. In medium bowl, mix brown sugar, butter, vinegar, salt, garlic powder and pepper. Reserve 2 tablespoons of the butter mixture. Add apples, sweet potatoes and onion to remaining butter mixture; toss to coat. Arrange apple mixture in roasting pan or 13x9-inch (3-quart) glass baking dish. Cover tightly with foil and bake 20 minutes.
Meanwhile, brush pork with reserved butter mixture. Heat 10-inch nonstick skillet over medium-high heat until hot. Cook pork in skillet about 3 minutes, turning to brown all sides evenly.
Place pork on apple mixture. Bake uncovered 30 to 40 minutes or until pork has slight blush of pink in center and meat thermometer inserted in center reads 160°F.