Gather the ingredients. Spray a 9”x 13” pan with nonstick cooking spray, or cover with foil.
Combine sugar and evaporated milk in a large, heavy-bottomed pot over medium heat. Stir continuously and boil for six minutes.
Remove from heat, and add butter, chips, and vanilla. Continue stirring until the chips and completely melted and the mixture is smooth.
Add the chopped nuts and stir to incorporate. Pour into prepared pan.
Ideally, this should cool at room temperature overnight, but if you are in a hurry or if it is especially warm, it can be put in the refrigerator to harden.