1packageminiature marshmallows, plain or multi-colored
Melt the chips with the sweetened condensed milk and margarine over low heat in a pot or in the top of a double boiler. If you are using a pot rather than a double boiler, keep a very close eye on the chocolate to make sure it doesn't burn.
Once the chocolate is fully melted, stir to mix it well with the condensed milk mixture. Remove it from the heat and stir in the vanilla and nuts. Cool it all just until it is lukewarm but still warm enough to mix with the marshmallows in the next step.
Place the marshmallows in a large bowl. Pour the chocolate mixture over the marshmallows and mix it all together.
Spread the chocolate marshmallow mixture in a wax papered lined 9" x 13" pan.
Chill until it is firm, about 2 hours. Once it has cooled and firmed, you can cut the "fudge" into squares for serving.
For those who have peanut allergies, use another nut. Chopped almonds, cashews, hazelnuts or Macadamia nuts would be delicious too.For a bit of fun and color, use multicolored mini marshmallows instead of the white. You can also add 1/4 cup of dried cranberries for texture, color and great flavor.