I personally like my cheesy chicken and rice best, you dice up boneless skinless chicken breast (about 1pound) and put it in a baking dish, put in 3/4c long grain rice, a can of cream of chicken, some chicken broth (I think about 1 1/2 cups, I'll check and get back to you lol), I season it with some black pepper and onion powder. Cover and bake for 50min on 375F, when it comes out I sprinkle a bunch of cheese on top and put the cover back on and let it set for about 5min for it to melt. It's really good. Oh I also put about a cup of frozen corn in before baking, or a can of it drained.
Another awesome one, which I guess it's not really a casserole lol, you just take chicken breasts, season them up really good, I use italian seasoning, salt, pepper, garlic powder, then put a can of cream of chicken soup on top and a splash of milk(less than 1/4cup), cover and bake for 45min on 350...serve with mashed potatoes, the cream of chicken makes like a gravy..it's awesome.
I made a really good mexican version of chicken and rice but it's a stove top recipe, not baked in the oven..so not a casserole but it was awesome