Preheat the oven to 350°F (175°C).

In a large pot, bring water to a boil and add the broccoli florets. Boil for about 2-3 minutes until they are bright green and slightly tender.

Drain the broccoli in a colander and run it under cold water to stop the cooking process.

In a mixing bowl, combine the cream of chicken soup, mayonnaise, garlic powder, onion powder, and black pepper. Whisk until smooth.

Add the shredded chicken and drained broccoli to the sauce mixture. Stir gently to coat everything evenly.

Transfer the mixture into a greased baking dish. Spread it out evenly and sprinkle the shredded cheddar cheese on top.

If using, sprinkle breadcrumbs over the cheese.

Bake in the preheated oven for 30 minutes, or until the cheese is bubbly and golden.