Line cookie sheet with foil. In 2-quart saucepan, melt baking chocolate over low heat, stirring constantly; stir in butter until melted and smooth. Remove from heat; stir in whipping cream. Pour mixture into small bowl. Refrigerate 10 to 15 minutes, stirring frequently, just until thick enough to hold a shape.
Drop mixture by rounded measuring teaspoonfuls onto lined cookie sheet. Return to refrigerator 5 to 10 minutes or until firm enough to shape. Shape into balls. Freeze uncovered 30 minutes.
In 1-quart saucepan, heat chocolate chips and shortening over low heat, stirring constantly, until chocolate is melted and mixture is smooth; remove from heat. Using 2 forks, dip and roll chocolate balls, one at a time, into melted chocolate; tap off excess chocolate. Place on lined cookie sheet. Immediately sprinkle with nuts. If chocolate has cooled too much, reheat. Repeat with remaining chocolate balls.
Refrigerate truffles about 10 minutes or until chocolate is set. Store in covered container in refrigerator. Remove from refrigerator about 10 minutes before serving.