Foolproof Chocolate Fudge

Line one 8 or 9 inch square pan with wax paper.
In a heavy saucepan, over low heat, melt the chocolate chips with the condensed milk. Remove from heat and stir in the chopped nuts and vanilla extract. Spread mixture evenly into the prepared pan and chill for 2 hours or until firm. Once firm, turn fudge onto cutting board, peel off waxed paper and cut into small squares.