She ranked highly on the track at the Japanese National Games, placing in the top three over 5000 m in 2004, 2006, 2007 and 2008.[2] A career breakthrough came at the 2009 Tokyo Marathon, which she won in a lifetime best of 2:25:38 hours.[5] She stuck to the longer distance, but managed only seventh at the Hokkaido Marathon (2:34:17). An improved performance came at the 2009 Chicago Marathon, where her finish in 2:29:22 hours brought her fifth place. Continuing mixed fortunes, Nasukawa was out of the top twenty in her attempted defence at the Tokyo Marathon, but took third at that year's Hokkaido Marathon.[2]
She was scheduled to run the Nagoya Women's Marathon to attempt to make the Japanese national team, but the race was called off following the 2011 Tōhoku earthquake and tsunami. Her hometown Oshu was badly affected and an old training partner of hers was killed alongside her daughter. Though deeply affected, Nasukawa vowed to run at the 2011 London Marathon, which had offered to host the national selection race.[6] In London she placed 18th overall in a time of 2:30:00 hours and did not make the Japanese Olympic team. She gave strong performances in 2012, running 2:28:44 hours for twelfth at the Nagoya Marathon, winning the Rock 'n' Roll Denver Marathon, and being runner-up to Lydia Cheromei at the Yokohama Women's Marathon with 2:26:42 hours (the second fastest of her career). Good form continued with a run of 2:30:27 for fourth at the 2013 Yokohama race.[2]
Nasukawa's career wound down thereafter. She won the 2015 low-profile Boulder Backroads Marathon, was down in 37th at the 2016 Nagoya Marathon, before finally calling time on her professional career with a time of 2:33:16 for fifth at the Saitami Women's Marathon.[1]