This is the second medal for team Nigeria at the ongoing World Athletics Championship in Kenya.
Nnamdi who set a National U20 record of 78.02m in qualifying on Thursday finished in the 3rd position with a throw of 74.48m.
He becomes the first Nigerian Athlete in 19 years to win a field event medal at the championship since Esther Aghatise won a medal in the long jump in 2002.
It would be recalled that he got a scholarship few days ago, by Baylor University in the US.
Team Nigeria 3 medals hopeful are women’s Favour Ofili in 200m, Imaobong Uko who set record of the fastest time in the ongoing World U20 athletics championship and Udodii Onwuzurike who has proven to be the best in the field with a new championship record of 20.1s.