The force’s commander, Gen Shehu Abdulkadir, confirmed the move to the BBC as West African military commanders met in Mali’s capital, Bamako.
France has almost 800 troops in Mali, and another 1,700 involved elsewhere.
It began its intervention last Friday with the aim of halting the Islamists’ advance south.
Nigeria now plans to provide 900 troops for the force, 300 more than previously announced.
The force is expected to be 3,300 strong. It will be deployed under UN Security Council resolution 2085, which was passed in December.