Pour Karo syrup and sugar into a medium saucepan and heat just until sugar dissolves. This will only take a minute or so. If you cook the mixture too long, the final cookie will harden too much.

Remove the mixture from the heat and stir in hazelnut spread until mixture is smooth. Measure cereal and place in a large mixing bowl. Pour sauce over cereal and mix until evenly combined.

Place scoops of the mixture onto wax paper to cool. Store in an air-tight container.