I have an idea, as we only have the common cold as an illness, maybe another illness could be implemented. I was thinking possibly rabies. If this is a terrible idea, please let me know.
Some wandering creatures are particularly aggressive and will attack your nicheling and infect it with the virus. The infected Nicheling could perhaps be fine to use for a few turns but will either pass away or turn, become unplayable and attack other nichelings. The only way to prevent it would be to perhaps have a certain type of immunity or kill the offending creature before it has a chance to attack.
