If the chicken broth is just old and has remained sealed in a can then the chicken broth even when old should be okay to eat.
The worst thing that would happen is you get sick and have a stomach ache, vomiting, stomach cramps etc.
But if the chicken broth is really bad then you could get food poisoning and even possibly die if you get sick enough.
If you think the chicken broth is bad then you should throw it out and not risk getting sick or possibly dying from it.
The chicken broth when bad will have a bad smell to it it.
So if you smell the chicken broth and it has a bad sour smell to it then throw it out because it's bad.