Nanjo was born in Uji, Kyoto, and began judo at the age of 5.[1] She belonged to Daicolo Co., Ltd. after graduating from University of Tsukuba in 1995.[1]
In 1997, she participated in the World Championships but was defeated by Carolina Mariani from Argentina.[2] In 1998, she also participated in the Asian Games held in Bangkok and won a bronze medal.
Nanjo was good at Seoi nage, Tomoe nage and Newaza,[1] learned by Shōzō Fujii[3] at Tenri University. She was known as a rival of Noriko Narazaki who is a classmate of the same university and former world champion.[1]
As of 2010, Nanjo coaches judo at Sendai University with her husband.[1]
- All-Japan University Championships (-52 kg) 1st
- Fukuoka International Women's Championships (-52 kg) 1st
- All-Japan Selected Championships (-52 kg) 2nd
- All-Japan Women's Weight Class Championships (-52 kg) 1st
- All-Japan Businessgroup Championships (-52 kg) 1st
- Fukuoka International Women's Championships (-52 kg) 1st
- All-Japan Selected Championships (-52 kg) 1st
- All-Japan Selected Championships (-52 kg) 1st
- Fukuoka International Women's Championships (-52 kg) 2nd
- Otto Super World cup Hamburg (-52 kg) 2nd
- All-Japan Selected Championships (-52 kg) 1st
- All-Japan Women's Weight Class Championships (-57 kg) loss
- All-Japan Women's Weight Class Championships (-52 kg) 5th
- Aral Grand Prix Prague (-52 kg) 1st
- All-Japan Selected Championships (-52 kg) 3rd