Preheat your oven to 375°F (190°C). While the oven warms up, bring a large pot of salted water to a boil for the pasta.
Add 8 oz of penne pasta to the boiling water and cook according to package instructions until al dente, usually about 9-11 minutes. Drain thoroughly using a colander and set aside.
In a large mixing bowl, combine the shredded chicken, green salsa, drained black beans, corn, 1 cup of the shredded cheddar cheese, sour cream, garlic powder, onion powder, salt, and pepper. Stir until everything is evenly incorporated and the sauce coats the ingredients well.
Add the cooked penne pasta into the bowl with the chicken mixture. Toss gently but thoroughly to ensure every piece of pasta is coated with the creamy verde sauce and mixed with the beans and corn.
Lightly grease your baking dish, then pour the pasta mixture into it, spreading it out evenly. Sprinkle the remaining 1/2 cup of shredded cheddar cheese on top to create a golden, bubbly crust.
Bake uncovered in the preheated oven for 20-25 minutes, or until the cheese is melted and slightly browned on top, and the casserole is heated through.
Remove from the oven and let it cool for a few minutes. For extra freshness and color, sprinkle chopped cilantro and diced tomatoes over the top before serving.