In small microwavable bowl, microwave remaining 2 cups chocolate chips on High 1 minute. Stir; continue to microwave in 15-second increments, stirring after each, until chocolate is melted. Spread over cereal layer. Refrigerate until chocolate is set and caramel mixture in center is firm, 2 to 3 hours. Let stand at room temperature 10 minutes before cutting. Cut into 6 rows by 4 rows.