Background: COVID-19’s emergence put unprecedented strain on Vietnam’s healthcare system, posing a variety of problems to the country’s nursing profession, potentially impacting nurses’ self-care and psychological well-being, and even putting their lives in jeopardy. When caring for many patients, nurses are constantly bombarded with information, producing cognitive overload in terms of safety. This has an influence on their physical and psychological well-being, as well as the risk of mistakes that compromise treatment quality and patient safety. Objectives: To assess the self-care, psychological well-being, and relationship between self-care and psychological well-being of nurse respondents caring for COVID-19 patients in selected hospitals in Binh Dinh, Vietnam. Materials and methods: A descriptive-correlational method was conducted on 180 nurses caring for COVID-19 patients from October 2022 to December 2022. Anchored on a four-point Likert scale, data were obtained using open-access and validated research instruments adopted from the self-care activities screening scale and psychological well-being assessment tool. SPSS software was used to process the data. Results: A total of 180 nurses participated in the study. The 135 participants were female, and 45 participants were male. Self-care was interpreted as "agree" in health consciousness, nutrition, physical activity, and sleep domains, with an overall mean of 3.21, 3.05, and 3.09, respectively. The psychological well-being was interpreted as "agree" in various domains, including autonomy, environmental mastery, personal growth, purpose in life, self-acceptance, and relations with others, with an overall mean of 2.81, 2.89, 3.09, 3.02, 2.85, and 2.89, respectively. Correlational analysis of the significant relationship on the assessment between self-care and psychological well-being of nurse respondents confirmed that: There was a statistically significant relationship between self-care and psychological well-being (p-value 0.000). Conclusions: The assessment of self-care and psychological well-being of nurses caring for COVID-19 patients in selected hospitals in Binh Dinh, Vietnam, confirmed that health consciousness was the strongest component of self-care, while nutrition was the weakest component of self-care; personal growth was the strongest component of psychological well-being, and autonomy was the weakest component of psychological well-being. Moreover, the significant relationships between the self-care and psychological well-being of nurse respondents caring for COVID-19 patients imply that an improvement in self-care would minimally enhance the psychological well-being of nurses.