The calculated distance (air line) between Oberwinterthur (Kreis 2) / Talacker and Sitten is approximately 110 miles respectively 177 kilometers.
By car or train, the actual journey to Sitten is certainly longer, as only the direct route (as the crow flies) between Oberwinterthur (Kreis 2) / Talacker and Sitten has been calculated here.
Air line (approximately)
177 kilometers
96 nautical miles