Background <p>Sustaining an engaged nursing workforce is essential for improving healthcare system performance and addressing global workforce shortages. However, limited evidence exists regarding the combined influence of motivation and organizational support on nurse engagement in Middle Eastern contexts.</p> Methods <p>A descriptive cross-sectional study was conducted among 166 registered nurses working in three tertiary hospitals in Saudi Arabia. Data were collected using validated scales measuring motivation, perceived organizational support, and work engagement. Pearson correlation and multiple linear regression analyses were performed.</p> Results <p>Nurses reported high motivation, moderate organizational support, and moderate work engagement. Organizational support was the factor most strongly associated with work engagement (β = 0.578, <i>p</i> &lt; 0.001), while motivation was not a significant independently associated factor in the multivariate model. Organizational support was positively correlated with both motivation and work engagement.</p> Conclusions <p>Organizational support is a critical job resource that significantly enhances nurse work engagement. Strengthening supportive work environments may improve workforce retention and healthcare system performance. These findings highlight the importance of system-level interventions in promoting workforce sustainability.</p> Clinical trial number <p>Not applicable.</p>