Position oven rack about 5 inches from broiler; preheat to 375°F. Coat a broiler-safe 9-by-13-inch baking dish with cooking spray. Add broccoli to a large saucepan; cover and cook, undisturbed, over medium heat until the broccoli is tender-crisp, 5 to 7 minutes. Remove from heat; set aside.
Meanwhile, stir cream cheese, Monterey Jack, ¼ cup Cheddar, sour cream, mustard, granulated garlic, onion powder, salt and pepper together in a large bowl until combined.
Add the broccoli, rice, chicken and broth; fold with a rubber spatula until evenly coated and no clumps of cheese remain. Spread the mixture in the prepared baking dish; top with the remaining ½ cup Cheddar. Cover tightly with foil. Bake until warmed through, about 30 minutes.
Remove from oven and remove foil. Increase oven temperature to broil. Broil until the cheese is bubbling and golden brown, 3 to 4 minutes. Sprinkle with bacon and scallions. Recipe developed by Catherine Jessee
