Preheat your oven to 350 and spray a 9x13-inch baking dish or casserole dish with nonstick cooking spray.
Cook rice according to package directions. (I like to use the Instant Pot to cook rice. Once I tried it, I haven't gone back to cooking it on the stovetop.)
Meanwhile, place a skillet over medium heat. Add olive oil and cook chicken until it is no longer pink inside. Season with salt, pepper, and garlic powder, if desired.
In a large bowl, combine all the rice, cooked chicken, cream of chicken soup, milk, and eggs.
Place the chicken mixture in the prepared pan and smooth the top with the back of a spoon. Top with shredded cheddar cheese and cover the dish with foil.