Preheat oven to 350°F (175°C) and lightly grease a 9x13-inch baking dish.

Cook frozen broccoli according to package instructions and drain thoroughly.

Bring chicken broth to a boil. Stir in instant rice, remove from heat, cover, and let sit 5 minutes.

While rice is warm, stir in butter and cubed Velveeta until smooth and melted.

Combine shredded chicken and broccoli in a large bowl. Add cheesy rice mixture.

Stir in cream of onion soup, cream of chicken soup, milk, and heavy cream until blended.

Spread mixture into prepared baking dish. Sprinkle Panko breadcrumbs on top if desired.

Bake 25–30 minutes until bubbly and lightly browned. Let sit a few minutes before serving.