He move up a weight class to welterweight for his next bout, against Jun Da Lion at NJKF WEST Young Fight 4th on August 19, 2018.
[3] Nakano briefly moved away from NJKF for his next fight, as he faced Kazuki Hamasaki at Hoost Cup Kings Osaka 3 on October 28, 2018.
He won the fight by a third-round technical knockout, as Hamasaki's corner threw in the towel at the 0:31 minute mark.
[4] His three-fight winning streak earned Nakano the opportunity to challenge the reigning NJFK welterweight champion TETSURO at NJKF 2018 West 4th on December 16, 2018.
[15] Nakano was booked to face Masaya Jaki at Rise World Series 2021 Osaka 2 on November 14, 2021.
He staggered Jaki with a left hook, before forcing a referee stoppage with a flurry of punches at the 2:16 minute mark.
[17] Nakano faced Chansuk for the vacant S1 super lightweight title in the main event of NJKF 2022 west 1st on February 5, 2022.
[22] Nakano faced Chadd Collins in a non-title bout at RISE WORLD SERIES 2022 Osaka on August 21, 2022.
Although Nakano was able to rise to his feet following a knockdown near the end of the opening round, he was visibly staggered, which prompted the referee to wave the fight off.
[28] Inai withdrew from the bout on April 12, as his eyesight had deteriorated due to a left rhegmatogenous retinal detachment.