Line an 8 in. x 8 in. or 9 in. x 9 in. square pan with parchment paper and spray with vegetable pan spray.
To prepare on stove: in heavy saucepan, heat Candy Melts in sweetened condensed milk over low heat, stirring until melted and smooth. Remove from heat.
To prepare in microwave: heat Candy Melts and sweetened condensed milk in 2 quart glass container on high power 2½-3½ minutes, then stir until melted and smooth. (Note: since microwaves vary in wattage and power output, cooking time may need to be adjusted.)
Stir in nuts and vanilla, if desired, then spread evenly into prepared pan. Refrigerate 2 hours or until firm. Turn candy out onto cutting board and peel off paper. Use cookie cutters to cut into shapes or cut into squares. Store in airtight container, at room temperature.