In 2004, Nelly Banco won the bronze medal in the 4 × 100 Metres Relay during the Junior World Championships at Grosseto. The French team, also made up of Natacha Vouaux, Lina Jacques-Sébastien and aurélie kamga, established a new French junior record for the discipline in 43 68 s. French Junior Champion in the 200m in 2005, Nelly won a new bronze medal in the 400m relay at the Junior European Championships at Kaunas. Under 21s Champion of France in the 100 meters and 200 meters in 2006, she finished second in the 200 m at the under 21s European Championship at Debrecen behind the Russian Yuliya Chermoshanskaya.