Preheat the oven to 375°F and grease a large baking dish.
Cook pasta according to package directions until al dente, then drain.
In a saucepan, heat olive oil and whisk in flour to make a roux. Slowly add milk, stirring until smooth and thickened.
Stir in cheddar cheese, parmesan, garlic powder, onion powder, salt, and pepper. Mix until creamy.
Combine pasta, chicken, and broccoli in the baking dish. Pour cheese sauce over and stir to coat.
Top with breadcrumbs and a little extra cheese if you like.
Bake for 25 minutes until bubbly and golden on top.
Let it rest for 5 minutes before serving.