Workplace violence against nurses, an ever-present problem in the healthcare workplace, has been increasing with COVID-19 and affects occupational health. This study analyzed the consequences of COVID-19 on violence against nurses, identifying its association with burnout, emphasizing the importance of work-related variables. A total of 1013 actively employed nurses in Spain with a mean age of 34.71 years filled out a computer-assisted web interviewing survey. Aggression as a consequence of their work was reported by 73.44% of the nurses. Those most affected were in primary care, and verbal aggression by patients and their families was the most frequent. Nurses who were attacked scored significantly higher in emotional exhaustion and depersonalization. Furthermore, 83.22% said that COVID-19 was an important factor in the increase in violence toward healthcare workers. Analysis showed that a perceived secure environment was a mediator between the belief that COVID-19 was an influential factor in the increase of violence and the depersonalization dimension of burnout. Increasing perceived security in the work environment among nurses can be effective in promoting well-being, work performance, and commitment to the profession.