Soak corn husks in hot water to cover 1 hour or until softened. Drain husks, and pat dry.
Spread 2 tablespoons Cornmeal Dough into a 3- x 5-inch rectangle on one side of 1 husk, leaving a 2-inch border at bottom narrow edge and a 1/2-inch border at one long side.
Spoon 2 heaping tablespoons Chicken Filling down center of cornmeal dough rectangle, creating a 1-inch-wide strip. Roll husk up, starting at the long side with 1/2-inch border, enclosing meat filling with the first turn. Fold bottom end with 2-inch border over, and secure with kitchen string or narrow strip of softened corn husk. Repeat procedure using remaining Cornmeal Dough and Chicken Filling.
Bundle together 6 filled corn husks, seam sides inward and open ends facing same direction, and secure with kitchen string. Repeat procedure with remaining filled corn husks, making 2 more bundles of 6 filled corn husks each.
Stand all 3 corn husk bundles, open ends up, in a large 12-quart stockpot. (If the bundles won't stand upright in the stockpot, place a 2-cup glass measuring cup upside down in the stockpot for the corn husk bundles to rest upon.)
Stir together tomato sauce, chili powder, and cumin. Pour tomato sauce mixture and 2 1/2 quarts water around corn husk bundles in stockpot. (Do not pour directly over corn husks.) Cover and bring to a boil over medium-high heat. Reduce heat to low, and simmer, covered, 3 hours. Remove tamales, discarding tomato sauce mixture.