A dear friend of mine would make this when we would get together. We would use semi-sweet chocolate chips and butterscotch chips. You can use whatever flavor you may like. I have made it with semi-sweet chocolate chips and peanut butter chips. As I said, which every flavor you like. At Christmas time I make it with a hole in the center, like a Christmas wreath and decorate it with holly leaves and berries, made with decorating icing.
Empty condensed milk and chips of your choice into a heavy bottom pot. Stir over medium heat just until melted. You aren't cooking it, just melting the chips. Stir until all melted and mixed. Remove from heat add nuts. Mix well. Pour into a 9 in. square or round pan that has been lightly buttered. Let cool. Cut into squares. Enjoy!