Preheat your oven to 400°F (200°C). Grease an 8x8 or 11x7 inch baking dish with olive oil.

In a large skillet, heat 2 tablespoons of oil over medium heat. Add chopped red onion, minced garlic, diced green bell pepper, and sweet red pepper, sauté for about 4 minutes.

Stir in chili powder, cumin, and cilantro, cooking for an additional minute until fragrant.

Add drained red beans and sweet corn to the vegetable mixture, heat through for a couple of minutes. Season with salt and pepper.

Prepare chipotle enchilada sauce if making homemade, otherwise use store-bought.

In a saucepan, whisk 1 cup of whole milk and 2 tablespoons of cornstarch over medium heat. Bring to a gentle boil, stirring until thickened (3-5 minutes).

Reduce heat and mix in shredded cheddar cheese until melted smoothly. Optionally fold in diced tomatoes and chilies.

In the greased baking dish, spread half of the enchilada sauce, layer half of the tortillas, half of the vegetable mixture, and part of the cheese sauce. Repeat layering, finishing with Monterey Jack cheese on top.

Cover with aluminum foil and bake for 20 minutes, then uncover and bake for an additional 5 minutes until cheese is melted and bubbly.

Allow to cool for about 5 minutes before serving. Garnish with fresh cilantro and serve with guacamole.