In a medium bowl, place chocolate chips, peanut butter and butter. Microwave in 30 second increments, stirring in between, until melted and smooth.

Chop box of cookies into small chunks (I cut into 9 pieces, 3 vertical rows and 3 horizontal, like a tic tac toe board).

In a very large bowl, pour your Chex and 1/2 of the chopped cookies. Use a large spoon to mix gently. Pour chocolate mixture over Chex. Use spoon to stir gently until all the cereal is fully covered.

Divide cereal mixture into two gallon-size Ziploc bags. Pour 1 1/2 c. powdered sugar into each bag. Seal, leaving air inside to create space, and shake. Shake until cereal is lightly white and doesn't look wet. Add more powdered sugar if needed/desired.

Open bags and divide remaining cookie pieces between bags. Close and shake to distribute cookies. 

Refrigerate at least 30 minutes before serving for best results!