Combine chicken, cream cheese, buffalo sauce, ranch dressing and 1 cup of shredded cheddar cheese in a slow cooker, stirring everything together well. Cover and set to LOW heat for 3-4 hours or HIGH heat for 1-2 hours. Check on it and stir every 30 minutes. When the cream cheese is fully melted and incorporated (no lumps), sprinkle the last 1/2 cup cheddar cheese over top, cover and cook until cheese is melted. Serve warm with chips, crackers or veggies for dipping. Serves 12-16.