Combine first 4 ingredients in a 4 qt. saucepan.
Stir over low heat until blended.
Bring to a boil over moderate heat,
being careful not to mistake escaping air bubbles for boiling.
Boil slowly, stirring constantly for 5 minutes
to soft ball stage). Remove from heat,
stir in chocolate chips, vanilla and nuts.
Keep stirring until chocolate chips are melted.
Pour into a buttered 9x9" pan and cool.
Yields approximately 5 pounds.