To prepare a hotter sauce: take 2 or 3 ladles of stock from the pan, and in a bowl mix with a good tablespoon of harissa (according to your taste) and some chick-peas. Serve with couscous for spicy sauce aficionados.
As for the chicken, choose a good quality one (free-range, of traceable origin, or "red label" in France for instance).
Proportions are given as suggestions, do not hesitate to adapt to your taste.
You can add other vegetables if you like: bell pepper, aubergine/eggplants, and other meats: meatballs, lamb, spicy sausage, beef...
If you can't find a ready-made mix of couscous spices, you can make your own from: cumin, coriander (ground), cinnamon, nutmeg, ginger, cardamom and turmeric. Paprika, cloves and caraway are also sometimes used.