Extradition to Nigeria (official: Federal Republic of Nigeria) is not excluded from the outset. Extradition to Nigeria would, however, only be possible on a non-contractual basis, since there is no extradition treaty with the Federal Republic of Germany for extradition to Nigeria.

No extradition treary with the Federal Republic of Germany

Extradition requests may have to be transmitted through diplomatic channels, requirements for extradition documents result from the Hague Convention of 05.10.1961. Pre-extradition detention could be ordered in Germany against a persecuted personon the basis of Nigeria's search at Interpol.

Actually, I have no information on extradition traffic between the two countries. It is well known, however, that Nigeria is looking for persecutees of various nationalities worldwide via Interpol. Amnesty International reports in its 2015/16 Annual Report on torture and ill-treatment by police and military in Nigeria.