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Nintedanib (NIB), a small-molecule tyrosine kinase inhibitor (TKI), is approved for idiopathic pulmonary fibrosis (IPF) and systemic sclerosis-associated interstitial lung disease. Although nephrotoxicity is uncommon, cases of nephrotic syndrome (NS), acute kidney injury (AKI) and glomerular lesions including thrombotic microangiopathy (TMA) and anti-glomerular basement membrane (GBM) nephritis have been reported. However, the optimal management of NIB-associated glomerular disease remains undefined. We report a 69-year-old man with IPF, hypertension, diabetes and underlying chronic kidney disease who developed persistent NS and renal dysfunction 16 months after initiation of NIB. Kidney biopsy demonstrated glomerular endothelial injury with microangiopathic features, accompanied by secondary collapsing focal segmental glomerulosclerosis (FSGS) and background diabetic kidney disease. Despite discontinuation of NIB and intensification of renin-angiotensin system inhibition and mineralocorticoid receptor blockade, nephrotic-range proteinuria persisted. Subsequent initiation of the sodium-glucose cotransporter 2 inhibitor (SGLT2i) dapagliflozin was temporally associated with a gradual and sustained reduction in proteinuria, with partial remission achieved while preserving the estimated glomerular filtration rate. To our knowledge, this is the first report of NIB-associated glomerular endothelial injury with secondary collapsing FSGS in which SGLT2i initiation was temporally associated with sustained proteinuria reduction under concomitant supportive therapy. TKIs may induce both endothelial and podocyte injury and therapeutic options beyond drug withdrawal remain limited. In this context, SGLT2 inhibition may represent a potential adjunctive therapeutic strategy in selected cases with underlying chronic kidney disease and warrants further systematic evaluation.