Season chicken with salt, pepper, and all other spices, tossing to coat fully.
Coat large saute pan with oil and bring to medium heat. Add chicken and cook through til no longer pink, about 7 minutes per side. Remove chicken to a platter, allow to cool.
Meanwhile, chop onion and mince garlic and set aside. If you're including them, remove the seeds from the chiles and mince them, then set aside.
Saute onion and garlic in chicken drippings until tender. Add corn and chiles. Stir well to combine. Add canned tomatoes, saute 1 minute.
Pull chicken breasts apart with forks into shredded strips. Add shredded chicken to saute pan, combine with vegetables. Dust the mixture with flour to help set.
Place a moist paper towel over the tortillas and microwave them on high for 30 seconds. This softens them and makes them more pliable. Coat the bottom of 2 (13 by 9-inch) pans with a ladle of enchilada sauce. Using a large shallow bowl, dip each tortilla in enchilada sauce to lightly coat. Spoon 1/4 cup chicken mixture in each tortilla. Fold over filling, place 8 enchiladas in each pan with seam side down. Top with remaining enchilada sauce and cheese.
Bake for 15 minutes or until cheese melts. Garnish with cilantro, chives, sour cream and/or chopped tomatoes before serving. Serve with Spanish rice and beans.