Trim fat from chops; sprinkle chops with pepper. Coat a large nonstick skillet with cooking spray; place over medium-high heat until hot. Add chops, in two batches, and cook until browned on both sides. Coat a 3 1/2- or 4-quart electric slow cooker with cooking spray. Place chops in cooker.
Combine barbecue sauce, tomatoes, and frozen vegetable blend, stirring well; pour mixture over chops. Cover and cook on high setting 4 hours. Or, cover and cook on high setting 1 hour; reduce to low setting, and cook 7 hours.