Preheat oven to 350°F. Spray a 13x9-inch baking dish with cooking spray.
Cook the frozen corn according to the package directions and transfer it to a medium bowl.
Open both 10-oz cans of green enchilada sauce. Measure out and set aside 1/2 cup of the sauce for the filling; keep the remaining sauce for the topping.
In the medium bowl with the corn, add 2 cups cooked, shredded chicken, the reserved 1/2 cup enchilada sauce, and 1 cup of the shredded Mexican blend cheese. Mix until combined.
If desired, warm the 6-inch flour tortillas briefly to make them more pliable. Spoon about 1/2 cup of the chicken–corn mixture down the center of a tortilla, roll it up, and place seam-side down in the prepared baking dish. Repeat with the remaining tortillas and filling.
Pour the remaining enchilada sauce evenly over the rolled enchiladas. Sprinkle the remaining 1 cup shredded Mexican blend cheese evenly over the top.
Bake uncovered for 15–20 minutes, or until the cheese is melted and the enchiladas are heated through.
Serve hot, topped with salsa, sour cream, and guacamole if desired.