Prep a square baking pan with foil which overlaps the sides of the pan. Then prep the foil with baking spray or butter.
Next, in a microwave safe bowl, combine together the sugar free chocolate chips, sugar free condensed milk, and the butter. We are going to melt these together. To do so microwave for about 2 1/2 minutes (or until melted), stopping to stir every 30 seconds.
Now pour the mixture into your prepped pan. Once the fudge is evenly distributed you can press in the remaining marshmallows and nuts. Refrigerate this for at least 2 1/2 hours and then cut into squares. Be sure to store this in the refrigerator. By the way, overlapping the foil in the first step will allow you to easily remove your fudge from the pan to cut into squares.
Please note that the nutritional data associated with this recipe is approximate and will in the end depend on the ingredients that you choose to use.
As mentioned, you will need sugar free marshmallows. You can make your own Sugar Free Marshmallows using this recipe. Simply make the marshmallows and cut them up small. Another option is to buy sugar free marshmallows online.