He and current partner Azusa Tanaka are the 2025 Asian Winter Games bronze mealists and two-time Japanese national silver medalists (2023–24, 2024–25).

[1] He attended Hinode Gakuen, a correspondence school recommended by fellow Japanese ice dancer Aru Tateno.

[1] Nishiyama was accepted into Waseda University's School of Human Sciences to study sports education and psychology, as he wants to become a skating coach.

[2][3] He is related to Japanese ballerina Akane Takada through his mother's side and has worked with her on improving body movement.

[3] 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.

Nishiyama moved to Canada alone at age fourteen to train with Brian Orser, Tracy Wilson, and Ghislain Briand at the Toronto Cricket, Skating and Curling Club, despite not knowing the language.

[5] After he suffered a hip injury in the fall of 2018 and was unable to practice jumps, another coach at the club, Andrew Hallam, suggested that he consider switching to ice dance.

[4] Despite Nishiyama's initial reluctance to switch disciplines, he drew inspiration from Japanese sprinter Dai Tamesue's book to adjust his mindset.

[15] Tanaka/Nishiyama made their international competitive debut on the Challenger circuit at the 2023 CS Golden Spin of Zagreb, coming ninth.