Prepare brownies in a 9x13 baking dish according to package directions for fudge like brownies. Cool completely.
In a mixing bowl or your stand mixer, beat together sugar, cream cheese, and peppermint extract until well blended.
Add in 1 1/2 cups Andes baking chips. Stir until combined.
Fold in 2 cups whipped topping.
Spread over top of cooled brownie.
In another mixing bowl, whisk milk and instant pudding mix until completely combined and thickened.
Pour over cream cheese layer and spread evenly.
Top the brownie lush with remaining whipped topped and Andes baking chips.
Refrigerate at least 4 hours prior to slicing and serving.