In a large bowl, measure cereal and set aside.
In 1-quart microwavable bowl, microwave chips, butter, and True Lemon juice uncovered on high for 1 minute; stir. Microwave about 30 seconds longer or until mixture can be stirred smooth. This can also be accomplished by using a double-boiler on the stove.
Pour mixture over cereal, stirring gently until evenly coated.
Pour chocolate-covered Chex into a 2-gallon resealable food storage plastic bag.
Add powdered sugar. Seal bag and gently shake until well coated. Spread on waxed paper or foil to let cool.
Store in airtight container.