If you are interested in letting your students self-assess their current well-being over the course of a semester or other time period, there are a number of simple questionnaires that have undergone significant reliability and validity testing.
These include the Warwick-Edinburgh Mental Well-being Scale (WEMWBS), a fourteen question instrument using a likert scale, the Ashridge Life Assessment Wheel, which uses a ten point scale across twelve indicators such as your satisfaction with family relationships to satisfactions your work and career and ten other indicators. The University of Michigan’s Health Promoting Lifestyle Profile (HPLP II) (Adult Version) is another example of a self-assessment questionnaire that uses responses (ranging from Never to Routinely) to 52 items to assess six different aspects of a health-promoting lifestyle ranging from physical activity to spiritual growth.
Compiling some averages and ranges across the students in your class could provide information for a rich discussion of the need for establishing self-care habits at the outset of a nursing career.