Nishiyama began skating in 2008 at the age of six, at the suggestion of his first coach Masahiro Kawagoe, who saw him attending a lesson at Citizens' Plaza in Shinjuku, Tokyo. He previously trained with Yutaka Higuchi in Tokyo, and qualified to compete at the Japan Championships each year. He was invited to skate in the gala at the 2013 World Team Trophy as the Japanese national novice champion in the same season.