As the number of nursing home residents with multiple healthcare needs grows, the demand for nursing expertise increases. The implementation of new care models involving nurses with expanded roles is crucial for ensuring quality care in nursing homes. To investigate the characteristics and activities of nurses employed in nursing homes in expanded roles and the factors associated with variation in the activities performed. This multicentre cross-sectional survey in Switzerland collected data from a convenience sample of 118 nursing homes between September 2018 and October 2019. From a subsample of 62 nursing homes, we analysed the characteristics and activities of 104 nurses in expanded roles. Associations between the activities performed and the educational background of the nurses in expanded roles, their direct supervisors' positions and the presence of physicians in the nursing homes were examined. Most Registered Nurses in expanded roles were diploma educated (48%), with fewer having a bachelor's (35%) or master's degree (17%). Overall, direct clinical practice and guidance and coaching activities were conducted monthly to weekly; consultation, evidence-based practice, collaboration and ethical decision-making activities were conducted monthly. We saw variations where a higher educational background was associated with more frequent evidence-based practice activities (z = 3.47, p < 0.001), and if direct supervisors were ward managers, nurses in expanded roles worked more frequently below their scope of practice (z = 4.10, p < 0.001). This is the first study to use Hamric's integrative Advanced Practice Nursing model to examine the activities of nurses in expanded roles in nursing homes. We found considerable variation in their activities, where nursing homes seem to adapt their roles to their educational background and the local context. Our findings show the importance of clarifying role expectations for Registered Nurses in expanded roles, allowing them to practice at the top of the licence to meet residents' complex healthcare needs.