Add the unsweetened chocolate, sugar, butter, and evaporated milk to a medium saucepan. Heat over medium-low heat until the chocolate is melted and everything is combined. Stir occasionally.
Remove from the heat and cool until lukewarm.
Grease a large mixing bowl and add 2 cups of graham cracker crumbs, mini marshmallows, and the chopped nuts.
Once the chocolate is cooled pour the cooled chocolate mixture over top of the graham cracker mixture. Mix until well combined.
Place in the refrigerator to chill for at least 1/2 hour.
Form into about 3-inch balls. Roll in the remaining graham cracker crumbs and set on a sheet pan lined with parchment paper.
Place in the refrigerator until firm.