Preheat oven to 350°F (175°C).
Cook and chop the chicken breasts; thaw and drain broccoli.
In a large bowl, mix cream of chicken soup, cream of mushroom soup, mayonnaise, and lemon juice until smooth.
Add chopped chicken, broccoli, and half of the shredded cheddar cheese; stir to combine.
Transfer mixture to a baking dish and spread evenly.
Sprinkle the remaining cheddar cheese on top.
Bake uncovered for 25-30 minutes or until bubbly and golden on top.
Let it cool for a few minutes before serving.