The calculated distance (air line) between Kostanjevica na Krki and Nova Gorica is approximately 86 miles respectively 138 kilometers.
By car or train, the actual journey to Nova Gorica is certainly longer, as only the direct route (as the crow flies) between Kostanjevica na Krki and Nova Gorica has been calculated here.
Air line (approximately)
138 kilometers
74 nautical miles