In South Korea, in 2019, approximately 45.5% of newly-graduated nurses quit their jobs within one year of employment. To better understand the adjustment to nursing practice upon graduation, we developed an online communication skills training program based on nonviolent communication and evaluated its effectiveness. A quasi-experimental design was adopted. The sample included 28 participants in the experimental group and 27 in the control group after one participant in the control group dropped out. The participants were fourth-year nursing students at the K and S University in Gyeonggi Province, South Korea, with some clinical training in a hospital setting. Data were analyzed using the χ2 test, Fisher's exact test, and independent t-test. Participants' empathy, communication skills, anger, and self-efficacy were assessed before and after the training, as well as across the two groups. The experimental group showed significantly higher levels of empathy, communication skills, and self-efficacy compared to the control group after the program completion. However, there were no significant differences in anger. This study suggests the effectiveness of the online version of the nonviolent communication training. Therefore, providing this program to nursing students scheduled for graduation may help retain newly-graduated nurses.