Place Cereal in a container that has a lid or in a bowl large enough to mix ingredients together in.
Melt white chocolate chips and butter together in a microwave safe bowl. I did 15 second intervals to allow me to stir and ensure the chocolate wasn't burning.
Mix key lime juice into the butter and chocolate mixture. (Add more or less lime juice based on personal preference).
Drizzle the chocolate lime mixture over the cereal, stirring to coat all the pieces on both sides.
Add powdered sugar a little at a time. Stirring to coat the cereal. (I place the lid on my container and give it a few shakes). Continue this process until you are out of sugar and have coated all the pieces.
If not eating immediately, store in fridge. The snack mix is best prior to storage in fridge as texture will be affected slightly.