In 10-inch nonstick skillet, heat oil over medium-high heat. Add onion; cook 2 to 3 minutes or until tender. Reduce heat to medium-low; stir in chicken broth, cream cheese spread, pepper and 1 1/2 cups of the Cheddar cheese. Stir frequently until cheese is melted. Add chicken; continue heating 3 to 5 minutes or until heated through. Transfer mixture to baking dish.