Chronic diseases are now the largest cause of mortality in Thailand, and form an increasingly large portion of the healthcare landscape. In the Thai health system, many patients with chronic conditions receive care and disease management services from nurses, yet specialized training in chronic diseases is not currently part of standard nursing degree programs. Given the evolving epidemiology of the Thailand population, we questioned whether practicing nurses remain confident in their knowledge and skills in chronic disease management. We conducted a cross-sectional, self-efficacy survey of nurses in eight randomly-selected provinces in Thailand, receiving 468 responses. Nurse self-efficacy was analyzed in prominent chronic disease types, including cancer, hypertension, diabetes, heart disease, cerebrovascular diseases, and pulmonary diseases. Factors, such as geographic location, education level, continuing education experience, and hospital size, were found to significantly affect nurse self-efficacy levels; nurses highly prioritized additional training in heart diseases and cerebrovascular diseases, followed by hypertension, cancer, and diabetes.