According to FIFA's rules any player who have not participated in competitive matches for one nation is eligible to play for another country they quality for provided proper clearance is obtained.

The Nigeria Football Federation has officially confirmed that Felix Agu is now eligible to play for the Super Eagles. Felix Agu currently plays for SV Werder Bremen in the German Bundesliga. His performance has led to his clearance he plays the position of a full back, Which means he can fit in left back or right back. What's your though on him guys?

https://www.brila.net/felix-agu-gets-green-light-to-play-for-nigeria-at-unity-cup/?utm_source=chatgpt.com