Beat egg whites until frothy. Gradually add sugar, beating until meringue stands in soft peaks; scrape bottom and sides of bowl occasionally with rubber spatula. Blend in baking powder and vanilla. Fold in crackers and nuts.
Drop mixture by rounded teaspoonfuls 1" apart onto two lightly greased baking sheets. Bake one sheet at a time in slow oven (300°) about 20 minutes. Remove from baking sheets at once and cool on racks.