Cut roast in half; place in a 3- or 4-qt. slow cooker. Mix chiles, taco seasoning and cumin; spoon over pork. Cook, covered, on low 8-10 hours or until meat is tender., Remove pork; cool slightly. Skim fat from cooking juices. Shred meat with 2 forks. Return to slow cooker; heat through. Serve in tortillas with lettuce and cheese. Freeze option: Place cooled pork mixture in freezer containers; freeze up to 3 months. To use, partially thaw in refrigerator overnight. Heat through in a covered saucepan, stirring gently and adding a little broth if necessary.