Nitta first competed in Super GT in 1994, the inaugural season of what was then known as the All-Japan Grand Touring Car Championship (JGTC) driving a Porsche 964 at Sportsland Sugo.

Nitta joined A'PEX in 1998, achieving a best finish of second at the Japan Special GT Cup at Fuji Speedway alongside co-driver Peter Dumbreck in the #44 Toyota MR2.

For the 1999 season, A'PEX formed a joint entry with Tsuchiya Engineering, and beginning at the All-Japan Fuji GT Race, Nitta would drive the #25 MR2 alongside Shinichi Takagi.

The racing division of A'PEX, which spun off from its parent company and rebranded as apr, ran the new Nissan-powered ASL Garaiya for ARTA beginning in 2003.

[6][7] During the 2006 season, Nitta drove a Toyota MR-S entered under the apr banner, and won the final round at Fuji after the R&D Sport Vemac 408R of Haruki Kurosawa and Shinsuke Shibahara ran out of fuel on the last lap.

His long association with apr ended after the 2014 season, and Nitta joined the LM corsa team in 2015 in their #51 BMW Z4 GT3 which was prepared by INGING Motorsport.

[citation needed] Nitta joined the new K-tunes Racing LM corsa team in 2018, which received technical support from INGING.

[12] Nitta made his GT World Challenge Asia debut in the 2022 season finale at Okayama, driving a new K-tunes Racing Lexus RC F GT3.