Prepare an 8x8-inch baking dish by lining with wax paper. Allow the wax paper to overhang about 1-inch on two sides of the baking dish.

Add the sweetened condensed milk to a medium-sized, heavy-bottomed saucepan and heat on medium-low heat. Stir in the chocolate chips and a dash of salt.

Reduce heat to low and stir mixture until chocolate melts completely into the sweetened condensed milk.

Remove chocolate mixture from the heat and stir in the vanilla. Next, stir in the chopped nuts if you are using them.

Carefully pour the chocolate mixture into the wax paper-lined dish, making sure to distribute the mixture evenly with a silicone or rubber spatula.

Cool the fudge to room temperature then refrigerate at least 2 hours.

When chocolate fudge has completely cooled and set, turn out onto a cutting board.

Cut into small squares (about 1/2-inch to 1-inch cubes).