Add chocolate chips, peanut butter, and coconut oil to a microwave safe bowl. Cook on high for 2 minutes, stirring halfway through. Stir until the chocolate chips are fully melted and the mixture is smooth.
Add the Chex cereal to a large bowl. Pour the melted chocolate on top. Using a spatula, gently mix so that all the cereal is covered (you will think you don’t have enough chocolate - I promise, you do! Keep mixing - you want the Chex to be fully covered, but not totally drenched in chocolate).
Pour the mixture into a large plastic bag (I recommend gallon size). Pour in the powdered sugar.
Close well and shake until all Chex are evenly covered with powdered sugar. They should almost have a grayish color. If some are super white and some don’t have any powdered sugar yet, keep shaking.
Pour back into a large bowl. Add the pretzels and peanuts and mix to combine.