Combine sugars, pineapple and juice, milk, corn syrup, salt, and butter in a 2-quart saucepan. Cook to 238 on a candy thermometer, stirring occasionally. Remove from heat and add marshmallows and vanilla. Mix together to melt marshmallow, then beat until mixture becomes heavy and creamy. Add nuts. Spread in a buttered 8-inch square pan. Cut into squares when cool and firm.