Final answer:
The nurse is applying the principle of Justice.
Step-by-step explanation:
The nurse is applying the principle of Justice in developing programs to reduce health disparities among different groups in the area. The principle of justice insists that the distribution and practice of healthcare should be equitable or fair. In this case, the nurse is working to ensure that all groups have equal access to healthcare and that the programs address the specific needs of each group in order to reduce disparities.