In small microwavable bowl, beat peanut butter, milk and 2 tablespoons sugar with wire whisk until smooth. Microwave uncovered on High 30 to 60 seconds, stirring after 30 seconds, to thin for drizzling. Drizzle mixture over filling. Drizzle with melted chocolate. Sprinkle with peanuts. Refrigerate about 1 hour or until set. For bars, cut into 6 rows by 4 rows. Store covered in refrigerator.