Measure rice chex into a large bowl; set aside.

In 1-quart microwave safe bowl, microwave chips and butter uncovered on High 1 minute; stir.

Microwave about 20 seconds longer or until mixture can be stirred smooth. Then stir in the lemon zest and lemon juice.

Pour the melted mixture over cereal, then carefully until evenly coated. Pour into 2-gallon resealable food-storage plastic bag.

Add powdered sugar. Seal bag; gently shake until well coated. Spread on a cookie sheet to cool. Once cooled, store in airtight container.