Sn-doped In2O3 nanowires have been grown on Si via the vapor-liquid-solid mechanism at 800 °C and then exposed to H2S between 300 to 600 °C. We observe the existence of cubic bixbyite In2O3 and hexagonal SnS2 after processing the Sn:In2O3 nanowires to H2S at 300 °C but also cubic bixbyite In2O3, which remains dominant, and the emergence of rhombohedral In2(SO4)3 at 400 °C. The resultant nanowires maintain their metallic-like conductivity, and exhibit photoluminescence at 3.4 eV corresponding to band edge emission from In2O3. In contrast, Sn:In2O3 nanowires grown on glass at 500 °C can be treated under H2S only below 200 °C which is important for the fabrication of Cu2S/Sn:In2O3 core-shell p-n junctions on low-cost transparent substrates such as glass suitable for quantum dot-sensitized solar cells.