There is no reason to go to Nishiwaki, there is nothing the tourist would want to see in Nishiwaki. But if there exists a typical mid-American town somewhere in the states, then this is the typical mid-Japanese town.
There is a river, a temple, some light industry. A short distance away, by train is Hezo-Koen which is the geographic centre of Japan. A little museum there has some work by local artists. Not the place to go if you are looking for excitement. Take the JR to Kagogawa and change there for the Kagogawa line to Nishiwaki.
There is a spur line that goes to Hezo-Koen.
photo by LERK