Line an 8 x 8-inch baking pan with parchment paper and set aside.
Melt half of the chocolate (about 6 ounces) in the microwave in 20–30 second intervals, stirring between intervals, until smooth. Pour the melted chocolate into the lined pan and spread into an even layer.
In a clean bowl combine the marshmallow fluff and Nutella. Microwave for 20 seconds, then whisk until fully combined and smooth. Spread this nougat layer evenly over the chocolate in the pan.
Place the unwrapped caramels and the milk in a bowl. Microwave for 30 seconds, then stir and continue microwaving in short bursts if needed until melted and smooth. Pour the caramel over the nougat layer and smooth with a spatula.
Freeze the pan for 1–2 hours, or until the layers are firm.
Remove the firm slab from the pan using the parchment paper and cut into 12 bars with a sharp knife.
Melt the remaining chocolate. Using two forks, dip each bar into the melted chocolate to coat completely, letting excess chocolate drip off, then transfer to a wire rack to set.
Let the chocolate coating firm before serving.