Kombucha or kefir soda or any other fermented drink would be good. Modern sports drinks are really modeled after traditional fermented drinks -- minerals and ions with a hint of sugars. Basically, for hydration, the traditional fermented drinks are perfect. When I'm sick, I use my palate as the guide to what I should be eating. If the kombucha seems too strong, I would dilute it a bit with water.
With bone broth, make sure you get it as clear as possible and skim off all the fats. When nauseous or very ill, anything remotely heavy or fatty can make you feel like throwing up. Also make it a bit less salty than usual.