In 5-quart saucepan, over medium heat, saute onion in oil 3 to 4 minutes or until translucent. Stir in chilies and taco seasoning mix; cook 1 minute. Add tomatoes, breaking up with spoon. Stir in turkey broth; bring to a boil. Add corn and turkey, reduce heat to low and simmer 5 minutes. Add cilantro.
To serve, spoon 1-1/3 cups soup in each bowl. Top each serving with 1/2 ounce tortilla pieces and 1 tablespoon cheese.