The approval comes after years of concerns about human rights abuses by Nigerian security forces.
The United States has approved a nearly $1bn weapons sale to Nigeria after legislators had put a hold on the deal over concerns about possible human rights abuses by the Nigerian government.
In July, the Senate Foreign Relations Committee and the House of Representatives Foreign Affairs Committee put a hold on the sale of 12 AH-1Z Cobra attack helicopters made by Bell.
On Thursday, the US Department of State made the determination that it would approve the sale of the attack helicopters worth $997m.
“This proposed sale will support the foreign policy goals and national security objectives of the United States by improving the security of a strategic partner in Sub-Saharan Africa,” a statement about the sale said.
Nigeria has been battling rising armed robberies and kidnappings for ransom in places where thinly deployed security forces have struggled to contain the influence of armed gangs.
Analysts have also said that the continuing invasion of Ukraine could lead to Nigeria sourcing arms imports from China due to sanctions on Russia and Belarus, which have had military partnerships with the West African state previously.
US officials have complained of “excessive force” by Nigerian military forces on unarmed civilians and called for restraint after soldiers in October 2020 opened fire on protesters demonstrating against police brutality in Lagos.