Chromoblastomycosis (CBM) is a granulomatous mycosis rarely described outside tropical countries. Degeneration into squamous cell carcinoma (SCC) is its most serious complication. We report the first case of nasal CBM degenerating into SCC. In 2006, a sixty-year-old male presented himself with an infiltrated plaque on the right thigh. The diagnosis of CBM was confirmed by the presence of fungal elements. In 2019, the patient had developed a mass coming from the right nasal cavity. It had rapidly involved the nasal dorsum. An ulcer-budding nasal tumor and an elevated erythematous and verrucous plaque on the thigh were noted. A biopsy revealed a granulomatous dermis with fungal elements. Other nasal biopsy fragments showed differentiated SCC. A fungal culture inoculated with tissue from both lesions showed dark colonies. The diagnosis of nasal CBM with SCC degeneration was reached. The patient presented asymptomatic endonasal CBM that had slowly evolved and recently degenerated.