In a large skillet over medium heat, sauté the diced onion and bell peppers in a little olive oil until soft, about 5 minutes. Add minced garlic and cook for an additional minute.
In a large 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. Stir until well combined.
Transfer the mixture into a greased 9x13 inch baking dish, spreading it evenly.
Sprinkle the shredded cheddar cheese over the top of the casserole.
Cover the baking dish with aluminum foil and bake in the preheated oven for 25 minutes.
After 25 minutes, remove the foil and bake for an additional 10-15 minutes until the cheese is bubbly and golden brown.
Once done, let it cool for a few minutes before serving. Garnish with chopped fresh cilantro if desired.
Notes
Serve hot directly from the baking dish, or portion into individual plates. A side salad or garlic bread pairs wonderfully with this dish.