1-Place Chex cereal in a large mixing: Place Chex cereal in a large mixing bowl and set aside. Line a work surface or baking sheet with parchment paper or wax paper.
2-In a gallon-size zip-top bag, combine powdered: In a gallon-size zip-top bag, combine powdered sugar and dry pistachio pudding mix. Seal bag and shake to mix.
3-Add almond extract to the bag, then: Add almond extract to the bag, then seal and shake again to incorporate.
4-In a separate medium microwave-safe bowl, combine: In a separate medium microwave-safe bowl, combine white chocolate wafers and butter. Microwave for 30 seconds, then remove and stir. Continue microwaving in 15-second increments, just until melted and smooth.
5-Pour mixture over Chex cereal in the: Pour mixture over Chex cereal in the large mixing bowl and gently stir to coat the cereal with the chocolate, working quickly before the chocolate hardens.
6-Transfer the cereal mixture to the zip-top: Transfer the cereal mixture to the zip-top bag. Seal bag and shake, coating the cereal with the sugar mixture.
7-Spread cereal mixture out onto lined surface: Spread cereal mixture out onto lined surface. Allow to cool completely.