Nishioka made his professional debut against Kento Koga at SHOOT BOXING YOUNG CEASER CUP CENTARL #13 on May 17, 2015.
[2] Nishioka extended his winning streak to two fights, after beating Asahi Hinuma by unanimous decision at SHOOT BOXING 2015～SB30th Anniversary～ act.4 on September 19, 2015.
[3] His winning streak was snapped by Toyozo Suzuki, who beat him by knockout at SHOOT BOXING YOUNG CEASER CUP CENTARL #15 on November 1, 2015.
[5] Nishioka faced YUSHI at SHOOT BOXING OSAKA 2016 “ALPINISME vol.1” on August 13, 2016, in his return to Shootboxing.
[6] Nishioka was scheduled to face GG Ito at SHOOT BOXING 2017 Young Cesar act.1 on March 11, 2017.
[9] Nishioka was booked to face Akinori in a DEEP KICK lightweight title eliminator at DEEP☆KICK 33 on July 16, 2017.
[11] Before challenging for the DEEP KICK title, Nishioka faced Kazuya Ueda at SHOOT BOXING 2017 act.4 on September 16, 2017.
[12] Nishioka challenged the Shootboxing Japan lightweight champion Kiyoaki Murata at SHOOT BOXING2018 act.4 on September 15, 2018.
[14] Nishioka face the ISKA Muay Thai Intercontinental Super Lightweight champion Haruaki Otsuki in a non-title bout at SHOOT BOXING S-cup 65 kg World TOURNAMENT 2018 on November 18, 2018.
[22] Nishioka's six-fight winning streak was snapped by Hikaru Machida at SHOOT BOXING GROUND ZERO TOKYO 2019 on December 3, 2019, who beat him by unanimous decision.
He was scheduled to face the reigning RISE Lightweight champion Kento Haraguchi in the tournament semifinals.