In a 400 degree oven, melt butter in a 9×13 glass baking dish.
Add onions to dish and bake uncovered, stirring occasionally, for 10-15 minutes or until onions are soft.
Place the chicken in dish and reduce the oven temperature to 350 degrees. Bake for 25 minutes.
Stir together chili sauce, brown sugar, vinegar, dry mustard and cranberries. Spoon over the pork chops and continue baking for 30 minutes or until meat is fully cooked and cranberry sauce has slightly caramelized.