1Grease bottom and sides of 8-inch square pan with butter.
2In 2-quart saucepan, heat milk, chocolate chips and unsweetened chocolate over low heat, stirring constantly, until chocolate is melted and mixture is smooth. Remove from heat.
3Quickly stir in nuts and vanilla. Spread in pan. Refrigerate about 1 hour 30 minutes or until firm. Cut into 8 rows by 8 rows to make 1-inch squares.