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 a few days ago, from Baylor University in the US.
Team Nigeria 3 medals hopeful are women’s Favour Ofili in 200m, Imaobong Uko who set a 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.