The 72-year-old Muhammadu Buhari, who defeated incumbent Goodluck Jonathan in elections two months ago, will be sworn in at a ceremony from 9am (0800 GMT) on Friday before world leaders and other dignitaries.
Among those who have confirmed attendance are South Africa's President Jacob Zuma, US Secretary of State John Kerry and French Foreign Minister Laurent Fabius.
The South African presidency released a statement saying: "In his congratulatory message, President Zuma expressed his commitment to working closely with president-elect Buhari to enhance the good bilateral relations which exist between South Africa and Nigeria, paying particular focus on the strengthening of economic co-operation.
"President Zuma also congratulated the people of Nigeria for conducting a peaceful, transparent, credible, free and fair election as declared by the Independent National Election Commission of Nigeria."
Soldiers were out in force on the streets, including at main entry points into the city, while there was a visible police presence at key locations such as hotels and government buildings.
Roads have been closed around the Eagle Square inauguration venue, where dozens of international flags have been hoisted alongside the Nigerian green, white and green tricolour