Hi,
There are various ways of adding chillies to dishes. Fresh chillies can be finely chopped and added to stews, for example. For a broth, I would recommend dropping whole green chillies like Jalapeno's into the broth. You can also add dried chilli powder to the broth - though you have to be careful with this depending on the spice rating of the chilli. I use chillies in various recipes - check them out at wwww.aromaandessence.com