Heat oven to 425°F. Spray 15x10x1-inch pan with cooking spray. In large bowl, mix mustard, oil, rosemary, garlic-pepper blend, seasoned salt and paprika. Reserve 1 tablespoon of the mustard mixture.
Add potatoes and onion to remaining mustard mixture in bowl; toss to coat. Place vegetables in pan.
Roast uncovered 25 minutes. Turn and stir potato mixture. Brush pork chops with reserved 1 tablespoon mustard mixture. Add pork chops to corners of pan.
Roast uncovered 15 to 20 minutes longer or until pork is no longer pink when cut near bone and vegetables are tender.