Background This study assesses the effectiveness of nurse-led intervention on self-management, self-efficacy, and blood glucose level among patients with Type 2 diabetes mellitus (DM) attending diabetic Out patient department (OPD) in Sri Ramachandra Hospital, Chennai. Methods In this study, the experimental group received nurse-led intervention on video-assisted teaching regarding nature of the disease condition including, diet, medication, hand and leg exercises, home care management, for 30 mins. Then a demonstration of hand and leg exercise was done followed by return demonstration done by the participants. The participants in the control group did not receive nurse-led intervention; they received only routine care. On the 15th day, when the patients came for the first follow-up, posttest was conducted for both the experimental and control groups. Results There was a statistically considerable difference noted in self-management (t=29.639; p<0.001), self-efficacy (t=28.293; p<0.001), FBS (t=2.415; p<0.05), and PPBS (t=2.102; p<0.05) in the posttest among patients with Type 2 DM in the experimental group. Conclusions The study concluded that the nurse-led intervention through video-assisted teaching is an effective method to recover self-management and self-efficacy as well as reduce the fasting blood sugar and postprandial blood sugar among patients with Type 2 DM.