Line a cookie sheet with wax paper or a Silpat or parchment paper. Set aside.
Take a large pot and put in your marshmallows and butter. Place the pot over medium-low heat and melt the butter and marshmallows together. Be sure to stir continually so the marshmallow doesn’t burn! Keep stirring until the mixture is blended and smooth. (It took about 5 to 6 minutes on my stove.) Remove the pan from the heat.
These next two steps happen very fast, so be sure you have all of your remaining ingredients measured out and ready to go. Add in the popcorn and nuts into your marshmallow mixture, and gently fold (or stir) them until they are completely coated in the marshmallow mixture. Then, add in the chocolate chips and continue to stir until the chocolate is melted and coating your mixture.
Grease your hands with butter or cooking spray. Shape the mixture into small popcorn balls – or simply take a spoon and drop your mixture in 1.5-to-2 inch clumps – and place them on the lined cookie sheet. Refrigerate your tray of treats for at least two hours, or overnight, and then serve.