The information logged by nurses on electronic health records (EHRs) using standardised nursing languages can help us identify the characteristics of highly complex chronic patients (HCCP) by focusing on care in terms of patients’ health needs. The aim of this study was to describe the profile of HCCPs using EHRs from primary care (PC) facilities, presenting patients’ characteristics, functional status based on health patterns, NANDA-I nursing diagnoses, health goals based on Nursing Outcomes Classification (NOC), and care interventions using Nursing Interventions Classification (NIC). With an observational, descriptive, cross-sectional, epidemiological study design, this study was carried out with a sample of 51,374 individuals. The variables were grouped into sociodemographic variables, clinical variables, resources, functional status (health patterns), nursing diagnoses, outcomes, and interventions. A total of 57.4% of the participants were women, with a mean age of 73.3 (12.2), and 51% were frail or dependent. Prevalent conditions included high blood pressure (87.2%), hyperlipidaemia (80%), osteoarthritis (67.8%), and diabetes (56.1%). The participants were frequent users of healthcare services, with 12.1% admitted to hospital in the past year. Some 49.2% had one to four health patterns assessed, with more information on biological and functional aspects than on psychosocial aspects. The mean number of nursing diagnoses was 7.3 (5.2), NOC outcomes 5.1 (4.1), and NIC interventions 8.1 (6.9). Moderately and highly significant differences were observed between dysfunction in physical activity/exercise health pattern and age group, and between dysfunction in other health patterns and classification as a frail or dependent elderly person. Regarding the presence of certain nursing diagnoses, significant differences were observed by age group, classification of elderly person status, and presence of diseases. A total of 20 NIC interventions showed moderately or relatively strong associations for older age groups, higher levels of dependency, and chronic health conditions.