1In a large skillet over med-high heat, saute onions in butter until onions are tender.
2Add in soup and 1 ½ cups cheese; gradually stir in milk.
3Cook over medium heat until cheese melts; stir in chicken and macaroni; taste and adjust seasoning with salt and pepper.
4Transfer mixture to a greased 2 ½ quart casserole; sprinkle with cracker crumbs.
5Bake in a preheated 350° oven for 30 minutes or until heated through.
6Top with remaining ½ cup cheese and bake 5 minutes.