Heat oven to 350°F. Combine sugar and butter in large bowl. Beat at medium speed, scraping bowl often, until creamy. Add sour cream, egg and almond extract; continue beating until well mixed. Reduce speed to low; add flour, baking soda and salt. Beat, scraping bowl often, until well mixed. Stir in chopped mangos and hazelnuts.
Drop dough by rounded teaspoonfuls, 2 inches apart, onto ungreased cookie sheets. Sprinkle with sugar, if desired. Bake for 10 to 12 minutes or until lightly browned.