The Trump administration is expanding its travel veto to five countries, Nigeria among them. Though we can’t know for sure why this country is targeted by the US foreign policy, we can speculate about its general geostrategic concerns: Nigeria has the potential to become the first African superpower, and the US hates to see African nations developing on their own, as their actions against Libya proves. If you combine Nigeria’s success with its close relations with US economic enemies like China, you get a regime change accident about to take place.
Conspiracy theory. No evidence is provided to support the claim. This message part of a recurrent Russian narrative to portray the US as a destabilising power. You can see other examples of disinformation about US plans and actions worldwide, such as its attempts to cause a massive African migration wave to Europe, its experiments on people in Georgia, its promotion of jihadist terrorism and colour revolutions, its preparations for war with Russia or its alleged responsibility in the China coronavirus outbreak.
The US government has indeed imposed new visa restrictions on a total of six more countries, including Nigeria, that failed to meet minimum security requirements for verifying travelers' identities and whether individuals posed a national security threat. According to the AFP Factcheck, a wave of misinformation hit Nigeria following this decision.
Regardless of these restrictions, the US has maintained good relations with Nigeria since its independence from the United Kingdom in 1960. The country is the United States’ second-largest trading partner in Africa and the third-largest beneficiary of U.S. foreign direct investment on the continent. The US is the largest foreign investor in Nigeria. The US provided almost 658,5 million dollars in assistance in 2019, and cooperation includes military training and counterterrorism advisory. Nigerians also comprise the largest African diaspora group in the United States, which has no interest in destabilising Nigeria or blocking its development.