In most nursing home cases, it is all about the standard of care. In South Carolina, a nursing home negligence case will generally have an experienced and knowledge nurse who testifies that there was a breach of the standard of care (if not multiple breaches). In this way, these cases resemble medical malpractice cases, except most of the time you are dealing with corporate wrongdoing as much as human error.
Couple of extra points: First, the expert requirement increases the complexity of these cases as well as increasing the expense. Normally, I will have two nurses review, although only one to testify. Sometimes, I may need a wound care expert or a pain expert or a dietician or even a doctor. And sometimes there are differences of opinion and it can take time and money to wade through all of the issues. So, a lawyer who takes these cases on must not only believe in the the truth and merit of the case, but he must have an experienced health care provider who validates his belief with an objective opinion based upon the facts of the case.