John put simply, the first step is that she requires an IELTS level 6.5 or above, then she could apply via an agency or directly to a Hospital, she would then need to apply for the relevant Visa, and Im sure they would help her with the application, she has to register with the NMC, Iv given you two links below, the first is The NMC and tells you all that you need to know Costs etc etc.

https://www.nmc.org.uk/registration/...ide-the-eueea/

https://www.jobs.nhs.uk/advice/overseas_cand.html