Seaon chicken with garlic pepper; place in crockpot. Add remaining ingredients, except half and half and cornstarch. Cover and cook on LOW for 6-8 hours.
Combine half and half and cornstarch in a container with a tight fitting lid 30 minutes before serving. Shake well. Stir mixture into crockpot. Cover and cook an additional 30 minutes until heated through and thickened.