Final answer:
The nurse must observe the principle of autonomy when confronted with an ethical decision in nursing.
Step-by-step explanation:
When confronted with an ethical decision, the fundamental principle a nurse must first observe is respect for people, which incorporates aspects of the other ethical principles.
This overarching principle ensures that a patient's dignity and rights are upheld above all. In clinical and research settings, ethical considerations such as autonomy, where patients have the right to make their own healthcare decisions, beneficence, which involves acting for the benefit and good of others, and nonmaleficence, where harm to others is avoided, all stem from the fundamental respect for people's rights and dignity.