[34] After making quick work of Fujimoto, and amassing a 6–0 professional record, Nasukawa was given the chance to challenge the reigning RISE Bantamweight champion Yuta Murakoshi.

[46] Nasukawa faced the reigning WBC Muay Thai International Super Bantamweight titlist Keisuke Miyamoto in a non-title bout at No Kick, No Life 2016 on March 12, 2016.

Miyamoto was originally expected to participate in the 2015 Blade Japan Cup, which Nasukawa eventually won, but withdrew with a fist injury.

[48] Nasukawa faced the undefeated Portuguese kickboxer Frederico Cordeiro for the vacant ISKA Oriental Rules Bantamweight (55 kg) title.

The contest was briefly stopped in the fourth round, due to an inadvertent clash of heads, which made it difficult for Nasukawa to see out of his right eye.

[50][15] Nasukawa faced the Italian national featherweight champion Tarik Totts (14–3–1) in a non-title bout in the main event of Rise 111 on May 29, 2016.

[77] Nasukawa faced the multiple-time World Kickboxing Network champion Ignacio Capllonch in the co-main event of Rise 121 on November 23, 2017.

He first faced the three-weight Lumpinee Boxing Stadium champion Suakim Sit Sor Thor Taew at Knock Out First Impact on February 12, 2018.

[83] Nasukawa faced the two-time Rajadamnern Stadium "Fight of the Year" winner Rodtang Jitmuangnon for the inaugural RISE Featherweight (57.5 kg) World Championship.

[14] Tenshin's behavior during the fight was controversial, as he was able to call his own time-outs, stalled for time, as well as telling the referee to stop the bout for groin shots which, in review, never occurred.

Analyst Jack Slack later wrote: "Tenshin Nasukawa was awarded the decision, keeping his undefeated record, but it was a hard sell and it came at the expense of the judges’ credibility.

[93] The tournament was expected to take place at three separate event, with Nasukawa being booked to face the World Kickboxing Network Oriental and Thai Boxing champion Federico Roma in the quarterfinals, which were held at the Ota City General Gymnasium in Ōta, Tokyo on March 10, 2019.

[97] Nasukawa next faced Martin Blanco at Rizin 16 - Kobe on June 2, 2019, for the vacant ISKA Featherweight (57 kg) World Championship.

[16] After notching back-to-back victories in Rizin, Nasukawa returned to RISE in order to face the three-weight Lumpinee Boxing Stadium champion Suakim PK Saenchaimuaythaigym in the semifinals of the World Series, which were held on July 21, 2019.

[106] The non-title bout was broadcast by Abema and was held in front of an empty arena, due to measures implemented to combat the COVID-19 pandemic.

[111][112] Nasuawa was booked to face the WBC Muay Thai World champion Kumandoi Petcharoenvit, in his fourth and final fight of the year, at Rizin 26 – Saitama on December 31, 2020.

[115] During the post-fight interview, Nasukawa announced that he was in the final year of his contract with RISE (which was set to expire 2022) and planned to fight twice more under their banner.

[118] Nasukawa faced the 2021 RISE World Series -53 kg tournament winner Kazane Nagai in his final fight with the promotion.

K-1 Japan group producer, Mitsuru Miyata, demanded that Nasukawa sign an exclusive contract with K-1 to be able to make the fight happen.

2 days later, K-1's official YouTube channel uploaded the full fight video of Takeru and Paskhaev but a few hours later it was deleted and re-uploaded without Masato's comments.

In an attempt to quash the cold war and influence K-1 and Rise to make the Takeru fight, Nasukawa made sure the show was being broadcast live so Rizin would not be able to cut any of his comments.

[129] On March 16, 2018, Rise president Takashi Ito, former K-1 fighter Hiroya and his lawyer, accused K-1 Japan Group's exclusive contract, illegal based on the competition law.

It was initially expected that the two-hour portion containing the main event would also be broadcast by Fuji TV,[135] who later backed out after allegations surfaced connecting RIZIN president Sakakibara with the yakuza.

Nasukawa knocked Takeru down with a left hook counter to his right straight in the very first round of the three-round affair, which proved the pivotal moment, as it edged the fight in his favor on all five of the judges' scorecards.

Rizin president Nobuyuki Sakakibara granted his wish and he won the fight against Dylan Kawika Oligo by guillotine choke in the second round.

[146] Founder, Chairman, and CEO of both Evolve MMA and ONE Championship, Chatri Sityodtong, stated that he is interested in signing Nasukawa after his contract expires.

Nasukawa passed after he successfully made the featherweight limit of 58 kilograms, scored 97 out of a possible 100 points on the written test, satisfied the physical examination and went through a three round sparring session with the future Japanese bantamweight title challenger Jin Minamide.

The contest took place on the undercard of the unified light-flyweight championship bout between Kenshiro Teraji and Hekkie Budler on September 18, 2023, at the Ariake Arena in Tokyo, Japan.

[160] Nasukawa revealed, during a talk show appearance on October 28, that he had suffered a left hand injury in the fourth round of his meeting with Aceves.

[163] Nasukawa is scheduled to face Jonathan "Torres" Rodriguez in a 10-round bantamweight bout at Ryōgoku Kokugikan in Tokyo, Japan on July 20, 2024.