Heat oven to 375°F. In 10-inch skillet, melt butter over medium-high heat. Add pork chops; sprinkle with salt and pepper. Cook 2 to 4 minutes, turning once, until browned on both sides.
In ungreased 8-inch square (2-quart) glass baking dish, layer sweet potato slices. Place pork chops over potatoes.
In same skillet, cook orange juice and brown sugar over medium heat until brown sugar is melted; pour over pork and potatoes. Cover dish tightly with foil.
Bake at 375°F. for 35 to 50 minutes or until pork is no longer pink and meat thermometer inserted into center of pork chop reads 160°F.
Remove pork chops and potatoes from dish; place on serving platter. Pour remaining liquid from dish into small saucepan; stir in yogurt. Cook over medium heat, stirring occasionally, until sauce is thoroughly heated. Pour sauce over pork chops and sweet potatoes.