The Central African Republic have stunned the Super Eagles with a 1-0 victory in their World Cup qualifying match at the Teslim Balogun Stadium on Thursday.
Namnganda's late goal sealed the shock victory for the visitors in the 91st minute of the game.
The victory ends the two-game winning streak of Gernot Rohr's side in their quest or a ticket to the showdown in Qatar next year.
However, Rohr's side who beat Liberia and Cape Verde in their opening matches remain top of Group C.
Nigeria will have the opportunity to make up for the loss when they face CAR on Sunday for the return leg.