Preheat your oven to 350°F (175°C) and prepare a 9x13 inch baking dish by greasing it lightly with cooking spray or oil.
In a large skillet, heat a drizzle of olive oil over medium heat. Add the diced onion and bell peppers, sautéing them until they have softened, about 5 minutes. Incorporate the minced garlic and sauté for another minute, until fragrant.
In a spacious mixing bowl, combine the sautéed vegetables with the shredded chicken, cooked spaghetti, corn, diced tomatoes, chicken broth, sour cream, smoked paprika, cayenne pepper, oregano, salt, and black pepper. Mix thoroughly until everything is evenly distributed.
Pour the mixture into the prepared baking dish, using a spatula to spread it out evenly across the dish.
Generously sprinkle the shredded cheddar cheese over the top of the casserole, ensuring a good coverage.
Cover the baking dish tightly with aluminum foil and place it in the preheated oven. Bake for 25 minutes to allow flavors to meld.
After 25 minutes, carefully remove the foil to allow the cheese to crisp and bubble. Return the dish to the oven and bake for an additional 10-15 minutes, or until the cheese is melted and a delightful golden brown.
Once removed from the oven, allow the casserole to cool for a few minutes to set before serving. If desired, sprinkle the top with freshly chopped cilantro for a burst of freshness.
Notes
Serve hot, optionally garnished with fresh cilantro.