[15] On September 26, 2010, she fought against Mayumi Aoki in the semi-final of the women's open-weight class first champion decision tournament of VALKYRIE 07, and won with an armbar.

[17] On December 30, 2010, in the VALKYRIE-sponsored match of the "Battlefield - Soul of Fight" event held at the Ariake Coliseum, she fought Mika "HARI" Harigai and won by Keylock submission.

This extended Nakai's winning streak from her debut to 10 and this achievement landed her on the front page of Tokyo Chunichi Sports the following day.

On September 4, 2011, Nakai fought Danielle West to a split-decision draw at "Pancrase - Impressive Tour 9".

[24][25] There was a good deal of controversy surrounding the bout however, as some journalists, and observers accused Pancrase of "fixing" the match.

[32] At UFC Fight Night: Hunt vs. Mir on March 19, 2016, she faced Leslie Smith and lost a 0–3 decision.

She defeated the decorated female wrestler Kanako Murata via 3rd round submission (Rear Naked Choke) to improve her record to 19-2.

She fought against Kim Ji-young, taking the mount position and winning the TKO with a series of elbow strikes.

At Deep Jewels 24, Nakai faced Kaewjai Prachumwong, defeating her via TKO stoppage in the second round.

[36] On October 22, 2019, she fought against Titapa Junsookplung (alias Diamond Rose the Rocket) at Deep Jewels 26 and defeated her with an armbar.

[37] She fought Shoko Fujita in the Deep-Jewels Flyweight Grand Prix quarterfinal bout at Deep Jewels 36 on March 12, 2022.,[38] winning by TKO.

She advanced to the final on the same day, defeating Shizuka Sugiyama via armbar at the end of the first round, winning the Grand Prix, and becoming the first Deep Jewels Flyweight Champion.