Heat oven to 375°F. Spray 8 medium muffin cups with cooking spray. In 1-quart saucepan, heat taco sauce with chicken over medium heat, stirring occasionally, until thoroughly heated.
Unroll dough and separate into 4 rectangles; press each into 8x4-inch rectangle, firmly pressing perforations to seal. Cut each in half crosswise, making 8 squares. Sprinkle both sides of each square with cornmeal. Press each in bottom and up side of muffin cup; turn edges of dough under, pressing to extend 1/4 inch above edge of cup.
Spoon about 2 tablespoons chicken mixture into each cup. Sprinkle cheese over each.