Preheat oven to 350°F. Spray a 9×13" pan with cooking spray. Combine dry ingredients. Set aside.
In a medium-sized bowl, mix melted butter, sugars, eggs, and vanilla. Add combined dry ingredients.
Add in 1 cup of the chocolate and mix well.
Pour into prepared pan and top with additional 1/2 cup of chocolate.
Bake for 25 minutes or until brownies are just set. Then add marshmallows and turn heat down to 250°F. Bake for 5 more minutes until marshmallows become soft and melt into one another.
In a double boiler, or a medium sized bowl placed over a pan with steaming water, add Nutella, chocolate chips, butterscotch chips, and butter.
Heat and stir until mixture is smooth. Remove from heat.
Add Rice Krispies cereal into bowl and stir well.
Dollop the crunch topping on top of the marshmallows and use a knife to carefully spread, being cautious to not completely smash the marshmallows.
Wait (as long as you can! ;) for chocolate to set before cutting. Serve and enjoy!