If any type of chicken is allowed at all (which isn't really clear from your post), such as diced chicken breast, just chuck some into the slow cooker with some dry cider. (Don't use sweet cider; it doesn't work). Add a few vegetables of your choice, with no great amount of 'peeling and chopping needed'. Leeks go well with it, as does celery, possibly with some carrots too. Lovely!
Sausage are cheap and easy to casserole in a slow cooker (and they come out beautifully) but it's easy to end up with a rather bland dish if you don't give the flavouring in the sauce you use a bit of clout. For me, the trick is to use some ordinary gravy granules but to make it with red wine instead of water (or, at least, a 50/50 mix). It only takes a few moments to chop some carrots to go in it (with no need to peel them). Adding some sliced onions, preferably browned in butter first (in a frying pan) can add to the flavour, as can throwing in some mushrooms.
Easy peasy!