You want to ask your prospective audience, not us!
Suggestion, though: cruise through these fora and see what professional issues topics get the most discussion-- licensure issues, ethical challenges, HIPAA (please, just the facts!), how nursing plans of care are differentiated from medical plans of care and why we care about that, hospice/palliative care, nontraditional nursing roles and jobs.... the choices are endless.
consider having an "expert". Nurse Practitioner, SANE nurse, Respiratory Therapist, Physical Therapist (our class had a PT come show us how to get people off the floor and other hints about transferring. Really informative)