Background/Objectives: The role of the primary health care nurse has evolved since the Spanish Ministry of Health officially established the professional profile of the nurse specialist in Primary Health Care in 2005. Despite the potential benefits of this new professional profile in the population’s health, their actual scope of practice is still unknown and still largely underutilized. This study aimed to explore demands and expectations of adult primary health care service users regarding the role of the nurse specialist in primary health care. Methods: A nationwide cross-sectional study consisted of a computer-assisted telephone survey to a random sample of 1200 adults living in Spain. A self-developed 19-item instrument assessed population’s perception of the role of the nurse specialist in primary health care. Descriptive, bivariate and logistic regression models explored associations between sociodemographic characteristics with perception of the nurse specialist role. Results: Most participants (82.3%) would choose a nurse specialist in primary health care and consider that the nurse specialist in primary health care should expand their scope of practice requesting diagnostic test (70%) and prescribing medications for chronic diseases (63.8%). Conclusions: Results show a population’s positive perception towards expanding the scope of practice of the nurse specialist in primary health care in the Spanish healthcare system. Primary health care models should acknowledge the potential of expanding the competencies of this professional profile.