Heat oven to 350 degrees F. Coat a 12 x 7 1/2 x 2-inch baking dish with nonstick cooking spray.
Spoon rice into prepared baking dish and spread evenly. Scatter about three quarters of the broccoli over the rice. Chop the chicken and layer on top of the broccoli.
In a large bowl, whisk together the soup, mayonnaise, milk, lemon juice and curry powder until blended and smooth. Pour evenly over casserole. Sprinkle remaining broccoli over top.
Bake at 350 degrees F, covered, for 30 minutes. Uncover and bake 15 minutes.