Nishiyama wanted to work using his voice since his 6th year of elementary school; in junior high school, he was suggested by a friend to become a voice actor. During high school, he participated in the Creative Course (which included voice actor and broadcast major) of his school. In 2009, while in high school, he participated in NHK's nationwide high school broadcast competition. In 2009, he participated in the 3rd 81 Audition and won a special award, after which he entered 81 Produce's training school. In May 2011, he joined the company 81 Produce. In 2015, he launched the entertainment group
"Ooimachi Cream Soda" along with Reona Irie and Yuu Taniguchi. As part of
Ooimachi Cream Soda, Nishiyama also acts in various stage plays. In 2016, Nishiyama released his first personal book
Nishiyama-san Chi no Koutaro-kun. In 2017, he published a photo essay book
Tarorizumu. In 2018, he won the Best New Actor Award at the 12th Seiyuu Awards. Nishiyama shared the award with
Taku Yashiro and
Shun Horie. In 2020, Nishiyama made his debut as singer from
Lantis with mini album
CITY. == Filmography ==