The aim is to conduct theoretical reflection on the inseparability among public health, planetary health and the nursing process in light of complexity thinking, with the aim of contributing to healthy and sustainable development. Study with a theoretical-reflexive approach that accessed bibliographical sources from contemporary authors who defend the inseparability between public health and planetary health and, at the same time, provide theoretical-systemic support to the nursing process, under an inductive critical bias. The nursing process is conceived as a complex phenomenon, which comprises interdependent dynamics, dialogical approaches, critical-reflective perception and prospective leadership. Theoretical reflection on the nursing process and sustainable development raises an expanded, contextualized and interdependent look at the role of nursing professionals in different health contexts, in order not to compromise well-being and environmental health.