Preheat your oven to 350°F (175°C).
In a large bowl, place the chopped broccoli and cooked rice. Mix them together gently.
In a medium saucepan over medium heat, combine both cans of condensed mushroom and chicken soups with chicken broth. Stir continuously until the mixture is well combined and starts to warm.
Gradually add in 1 cup of shredded cheddar cheese, cream cheese, minced garlic, onion powder, and butter. Keep stirring until everything is melted and smooth.
Once your sauce is ready, pour it over the broccoli and rice mixture. Mix everything together until well coated.
Transfer the mixture into a 9×13 baking dish, spreading it out evenly.
Top the casserole with the remaining shredded cheddar cheese.
Cover the dish with aluminum foil, then bake for 40 minutes. This allows the flavors to meld.
After 40 minutes, remove the foil and bake for an additional 5 to 10 minutes until golden and bubbly.
Let it sit for a few minutes before serving.