The US Embassy in Nigeria via their official website releases statement telling Nigerians willing to travel to the US with valid visas to go ahead and make the trip.

The U.S. Embassy in Abuja wishes to clarify that there is no reason for Nigerians with valid visas to postpone or cancel their travel to the United States. Nigeria is not named in the Executive Order on Immigration issued on March 6, and there is no prohibition against Nigerian lawful permanent residents or persons with a valid visa or other U.S. government authorization from entering the United States.

Source:- UsEmbassy