Heat oven to 350 degrees. Spray 13-by-9-inch pan with nonstick cooking spray.
In large bowl, stir cookie mix, oil, water, and egg until soft dough forms. Press dough into prepared pan. Bake 15-20 minutes, or until set.
Sprinkle marshmallows over crust. Bake 1-2 minutes until marshmallows begin to puff. Remove from oven.
In 4-quart saucepan over low heat, heat corn syrup, butter, vanilla, and peanut butter chips, stirring constantly until chips are melted and smooth. Remove from heat.
Stir in cereal and peanuts; spoon mixture evenly over marshmallow layer. Refrigerate 30 minutes, or until firm. Cut into bars and serve.