Introduction Smartphones have significantly increased digital engagement among young people due to their ease of use and constant internet access. Nomophobia and the fear of missing out are associated with mobile and internet use, potentially impacting students’ mental health and academic performance. Objectives To provide the prevalence of nomophobia and fear of missing out while shedding light on the role of psychological alienation between them. Methods A multisite descriptive correlational study was conducted among 1,273 undergraduate nursing students at six Egyptian universities: North Sinai, South Sinai, Port-Said, Suez Canal, Suez, and Damanhur University, Egypt. From June 2023 to November 15, 2023, the students were surveyed using questionnaires on nomophobia, fear of missing out, and psychological alienation. Results Nursing students experienced moderate to severe levels of nomophobia (37.4%–45.3%) and psychological alienation (45.8%–55.4%). There was a significant positive correlation between nomophobia and fear of missing out ( r = .908, p < .001), as well as between nomophobia and psychological alienation ( r = .377, p < .001). Psychological alienation was also found to mediate the relationship between fear of missing out and nomophobia, with the indirect effect being statistically significant (indirect effect = 1.000; p < .001). Conclusion The study highlights the significant prevalence of nomophobia and psychological alienation among nursing students. The findings underscore the complex interplay between digital connectivity issues, psychological disconnection, and the fear of missing out. In addition, findings suggest that psychological alienation plays a crucial role in how fear of missing out impacts nomophobia among nursing students.