Preheat oven to 375 degrees F. Cut 15 of the maraschino cherries in half; set aside for topping cookies. Chop remaining maraschino cherries.
In a large bowl, stir cookie mix, oil, water, and egg until soft dough forms. Stir in chopped cherries and nuts. Drop dough by rounded teasponfuls 2 inches apart on ungreased cookie sheet. Press one cherry half lightly into center of each cookie.
Bake 7 to 9 minutes or until set. Cool 2 minutes. Remove from cookie sheet to wire rack. Cool completely, about 15 minutes.
Before serving, sprinkle with powdered sugar. Store loosely covered at room temperature.