Add butter, chocolate chips, milk, and salt to a medium-sized cast iron skillet and cook over medium-low heat, stirring until smooth. Once smooth, top with a layer of mini marshmallows and transfer skillet to oven.
Broil for 1-2 minutes or until marshmallows have softened and browned.
To make the caramel sauce & nuts, cook the brown sugar, melted butter & milk on medium heat until thick , 1-2 minutes.
Drizzle the caramel sauce over the s’mores & sprinkle the nuts over top.