I just re read your original post and also wanted to say that remember, the worst that could happen is for her to say no. Then what? You look for another job. Maybe part time? You are, as stated, a skilled and experienced nurse, and there is always a need for nurses.
I really feel for you and just want you to know that it will work itself out. Everybody has their issues, people have babies, people get sick, etc etc.. Everyone hits hard times so you are not the first person to ask for their job back. **** happens.
They already know you and know that you know the job
And come to think of it, I did a similar thing several years ago where I quit saying I needed to go and take care of a family member but actually went to rehab. Three months later I came back and was hired by the same company, but different department (I'm a social worker). So yes, you can do it.
And even if you do have to do another orientation, it is much easier on the supervisor to hire someone who has already done the job. Good luck!