Preheat your oven to 375°F (190°C). Lightly grease a 9x13 inch baking dish and set aside.

Cook the pasta according to package directions in a large pot of salted boiling water until al dente. In the last 2 minutes of cooking, add the broccoli florets to the boiling pasta water to blanch. Drain well and set aside.

While the pasta cooks, heat olive oil in a large skillet over medium-high heat. Add the cubed chicken, season with 1/2 tsp salt and 1/4 tsp black pepper. Cook, stirring occasionally, until the chicken is cooked through and lightly browned, about 5-7 minutes. Remove chicken from the skillet and set aside.

Reduce heat to medium. Add 4 tbsp butter to the same skillet (no need to wipe clean if there are browned bits from chicken, they add flavor). Once melted, sprinkle in the flour and whisk constantly for 1-2 minutes to create a roux.

Gradually whisk in the milk and chicken broth, a little at a time, until smooth and no lumps remain. Bring the mixture to a gentle simmer, whisking frequently, until it thickens, about 3-5 minutes.

Reduce heat to low. Add the cubed cream cheese, garlic powder, onion powder, and smoked paprika. Whisk until the cream cheese is completely melted and incorporated into the sauce.

Remove the skillet from heat. Stir in the shredded cheddar cheese and 1/2 cup grated Parmesan cheese until fully melted and the sauce is smooth and creamy. Taste and adjust seasoning if needed.

In the prepared baking dish, combine the cooked pasta, blanched broccoli, cooked chicken, and the creamy cheese sauce. Stir gently until everything is evenly coated.

In a small bowl, mix together the panko breadcrumbs, 1/4 cup grated Parmesan cheese, and 2 tbsp melted butter. Sprinkle this mixture evenly over the top of the pasta bake.

Bake for 20-25 minutes, or until the sauce is bubbly and the topping is golden brown. If the topping is browning too quickly, you can loosely cover it with foil.

Remove from oven and let stand for 5-10 minutes before serving. This allows the sauce to set slightly.