Bring a large pot of salted water to a boil. Add 2 cups of macaroni and cook until al dente, about 7-8 minutes. Drain and set aside.
Heat 1 tablespoon of olive oil in a skillet over medium heat. Add 1/2 cup chopped onions and 1 cup chopped bell peppers. Sauté until softened and fragrant, about 4-5 minutes. Add 1 cup corn kernels and cook for another 2 minutes. Remove from heat.
In a large mixing bowl, combine the cooked macaroni, sautéed vegetables, 2 cups cooked shredded chicken, 1 cup barbecue sauce, 1 teaspoon garlic powder, 1 teaspoon onion powder, salt, and pepper to taste. Stir gently to combine everything evenly.
Fold in 1 cup shredded cheddar cheese, reserving a small handful for topping later. If using, add 1/2 cup cooked and crumbled turkey bacon into the mixture.
Preheat your oven to 350°F (175°C). Transfer the mixture into a greased 8x8-inch baking dish. Sprinkle the reserved cheddar cheese on top evenly. Bake uncovered for 20-25 minutes, or until the cheese is melted and bubbly with lightly browned edges.
Let the casserole cool for a few minutes before scooping. Serve with a fresh green salad or steamed veggies for a complete meal.