Preheat your oven to 350°F (175°C).
In a large bowl, combine the shredded chicken and broccoli florets.
In another bowl, mix together the mayonnaise, cream of chicken soup, milk, lemon juice, garlic powder, salt, and pepper.
Pour the sauce over the chicken and broccoli mixture, stirring to combine.
Transfer the mixture to a greased 9x13 inch baking dish.
Sprinkle the shredded cheddar cheese evenly over the top.
Add breadcrumbs on top of the cheese for a crunchy texture.
Bake in the preheated oven for 25-30 minutes, until bubbly and golden brown.
Allow to cool for a few minutes before serving.
Garnish with fresh herbs if desired.