Full report: US Visa Ban on Nigeria.

(i) *Nigeria does not comply with the established identity-management and information-sharing criteria assessed by the performance metrics. Nigeria does not adequately share public-safety and terrorism-related information, which is necessary for the protection of the national security and public safety of the United States.* Nigeria also presents a high risk, relative to other countries in the world, of terrorist travel to the United States. Nigeria is an important strategic partner in the global fight against terrorism, and the United States continues to engage with Nigeria on these and other issues. The Department of State has provided significant assistance to Nigeria as it modernizes its border management capabilities, and the Government of Nigeria recognizes the importance of improving its information sharing with the United States. Nevertheless, these investments have not yet resulted in sufficient improvements in Nigeria’s information sharing with the United States for border and immigration screening and vetting.
(ii) *The entry into the United States of nationals of Nigeria as immigrants, except as Special Immigrants whose eligibility is based on having provided assistance to the United States Government, is hereby suspended.*

Full report :
https://www.whitehouse.gov/presidential-actions/proclamation-improving-enhanced-vetting-capabilities-processes-detecting-attempted-entry/
*e) Nigeria*