Place potatoes in a 5- or 6-qt. slow cooker coated with cooking spray. In a large nonstick skillet, brown pork chops in oil in batches., Place chops over potatoes. Saute onions in drippings until tender; place over chops. Melt butter in skillet. Combine the flour, salt, pepper and broth until smooth. Stir into pan. Add milk. Bring to a boil; cook and stir for 2 minutes or until thickened. , Pour sauce over onions. Cover and cook on low for 8-10 hours or until pork is tender. Skim fat and thicken cooking juices if desired.