The calculated distance (air line) between Umm Kaddadah and An Nuhūd is approximately 133 miles respectively 214 kilometers.
By car or train, the actual journey to An Nuhūd is certainly longer, as only the direct route (as the crow flies) between Umm Kaddadah and An Nuhūd has been calculated here.
Air line (approximately)
214 kilometers
115 nautical miles