Preheat your oven to 375 degrees F. Lightly grease your baking pan with cooking spray so the tortillas don't stick.
In a skillet add your olive oil and heat to medium. Once the oil is hot add your onions. Cook for 6-8 minutes or until the onions are translusent and tender. Add a teaspoon of the taco seasoning to the onion and toss to coat.
Add your bell pepper to the onion. Cook the bell pepper for 5-7 minutes.
Add the frozen corn to the bell pepper and onion. Add another teaspoon of taco seasoning. Toss to coat.
Once the veggies have cooked, add the black beans. Add another teaspoon of taco seasoning.
Add half the can of enchilada sauce to the bottom of your baking dish.
Now you're ready to start assembling your tortilla shells. Add some of the veggie filling to the tortilla shell, top with a sprinkle of cheese and roll the tortilla. Place the rolled tortilla in the baking dish with the enchilada sauce, seam side down.
Add the remaining sauce on top of the rolled tortilla shells in your baking dish. I like to make sure the enchiladas are pretty much covered with the sauce so they don't get dry. Add the remaining cheese to the top.
Bake the enchiladas uncovered for 20-30 minutes. Once the cheese has melted and the sauce is bubbling they are done.
Allow the enchiladas to cool for 5-10 minutes before serving. Add cilantro or guacamole to the top.