PREHEAT oven to 325° F.
SPRINKLE flour over cutting board or kitchen work surface. Break off two rows of cookie dough. Roll out dough to about 1/8-inch thickness, using additional flour as needed to prevent sticking. Press cookie cutters into dough and transfer letters to ungreased baking sheets with spatula.
BAKE for 8 to 10 minutes or until golden. Cool on baking sheets for 2 minutes; remove to wire racks to cool completely.
COMBINE sugar, Nesquik and water in medium bowl; beat with whisk or hand-held mixer until smooth. Spread icing over cookies. Allow icing to dry before adding any additional decorations.