In a small bowl combine mustard, Italian dressing, and pepper; set aside.
Trim excess fat from chops.
Spray a 10 inch skillet with nonstick spray coating.
Preheat the skillet over medium high heat.
Add the pork chops and brown on both sides.
Remove chops from skillet.
Add onion to skillet.
Cook and stir over medium heat for 3 minutes.
Push onion aside; return chops to skillet.
Spread mustard mixture over chops.
Cover and cook over medium low heat for 15 minutes or till pork is no longer pink.