In a medium sized pot add butter and mini marshmallow and melt over low heat stirring continuously to avoid sticking. Once melted, add to a large mixing bowl with rice krispie cereal and stir to combine. Set Aside.
In an 9x9 (or loaf pan) greased pan sprinkle 2 tbsp mini chocolate chips. Add rice krispie mixture into the pan and press until even.
In a small saucepan add remaining mini chocolate chips with Nutella and warm until smooth. Pour over rice krispie mixture and cool in fridge until chocolate has set, about 30 minutes. Once set, slice and serve, enjoy!
Optional: Sprinkle melted chocolate over the top of the finished rice krispie treats. Simply melt chocolate chips in a small bowl in the microwave and use a spoon to drizzle over the top.