Does she have grounds to appeal the mark? The potential success of this will be based on whether she does. Her university, students union and tutors will be best to advise her on this.
If she has the opportunity to resubmit in March then if an appeal is unsuccessful this will be her only option if she wants to be a nurse. She should seek feedback on her most recent submission so that she has guidance to successfully submit it on resubmission. With regards to her job, she will need to speak to them and see whether they are willing to wait until march for her to be registered (it’s possible with how nursing currently is that they will), if they don’t keep the post open it’s not the end of the world, there are loads of vacancies within nursing at the moment, I doubt she will struggle to find work as a registrant following her resubmission.