Background: Nurses experiencing second victimization after a patient safety incident face challenges in developing effective coping strategies. Active coping can lead to constructive practice changes within a just culture. However, no theoretical model has yet tested the relationships among a just culture, second victim variables, coping strategies, and practice changes. Methods: A nationwide online survey was conducted using proportional quota sampling based on region, representing 0.7% of nurses in tertiary hospitals across various Korean regions as of August 2022. Partial least squares structural equation modeling (PLS‐SEM) was used to develop the hypothesized model, determine the model fit, and test research hypotheses. Descriptive statistics, model fit, and path analysis were performed using SPSS and Smart‐PLS. Results: The final analysis included 461 clinical nurses. Six significant pathways were identified: A just culture positively influenced constructive changes in nursing practice through second victim experience and avoidant coping ( B = 0.07, p < 0.001). In the absence of a just culture, constructive changes decreased ( B = −0.12, p < 0.001). The just culture negatively influenced defensive changes in nursing practice through second victim experience ( B = −0.24, p < 0.001). The just culture negatively influenced defensive changes in nursing practice through second victim experience and avoidant coping ( B = −0.10, p < 0.001). Without the just culture, defensive changes in nursing practice increased ( B = 0.19, p < 0.001). The just culture reduced avoidant coping through second victim experience ( B = −0.25, p < 0.001). Conclusions: This study provides pathways to increase constructive nursing practice changes and decrease defensive nursing practice changes in nurses who have experienced a patient safety incident. Implications for Nursing Management: The just culture needs to be established in a nursing practice setting and healthcare organizations. This study, using a representative sample through proportional quota sampling, provides reliable and valid evidence for nursing practice and healthcare organizations regarding the just culture, second victim experiences, and patient safety.