Obviously, the chicken stock can be used as a base for all kinds of soups, not just chicken soups, served with crusty bread, matzo balls, dumplings or noodles.
If you want to turn it into a heartier, main meal my favourites are:
Ramen noodles with shredded chicken, a soft boiled egg, mushrooms, spring onions and pak choi. You can use pretty much any vegetable though, even frozen peas. You can use any flavourings, eg soy sauce, ginger, chilli, you like (google for ideas) but plain is good for little ones and fussy eaters.
Spanish garlic soup - make croutons by tossing cubes of bread in oil or garlic butter and baking, fry 6 cloves of garlic finely chopped until golden, add shredded ham or chopped streaky bacon (1 or 2 rashers per person) fry until heated through/cooked, add a tsp or 2 of smoked paprika (optional for fussy eaters) and the croutons, cook for a minute then add 1.5l of chicken stock, season with salt and pepper, heat through. Then break an egg per person into the soup, cover with a lid and poach. If it's easier for you, you can poach the eggs separately then add them to the soup or use soft boiled eggs.