Yeah, are you sure the chicken broth was the reason it burned? I have often burned my rice without using chicken broth as the liquid.
I don't burn my rice when I use the rice cooker to cook rice using water.
When I use chicken broth, usually the rice at the bottom of the rice cooker gets a bit burnt.
I cannot control the heat as my rice cooker only has an on/off switch. No temperature setting.
A friend of mine suggested that I steam my rice instead. I'll also try the stirring method ButtrflyDreams suggested, tho I don't usually open the lid of the rice cooker.