That is a very generic way of telling someone that s/he is no longer being considered for a position. It may mean anything or nothing at all.
I suggest you let a week or so pass to allow the "sting" to fade. Then, if you believe you had a good rapport with the nurse manager and/or human resources person, send a professionally worded e-mail thanking them for their consideration and asking if it would be possible to learn what you might work on in order to be better prepared for future interviews.
If they truly feel invested in you and would like to consider you for future positions, they may respond.
Don't take any of this personally. Reasons for being declined span a wide range, and include many factors that are entirely out of your control (and sometimes even the control of the manager.) The CEO's daughter may have just graduated nursing school
Hang in there!