Asisat Oshoala doubled Nigeria’s lead two minutes from the end of the exciting first half.
Cameroon coach Enoh Ngatchu said reaching the World Cup for the first time in a decade can help transform the game in his country.
Ngatchu told BBC Sport: “We have more girls playing soccer, we are better organised – with this qualification, many things will change.”
Nigeria and Cameroon had already qualified for next year’s World Cup in Canada by reaching the final.
They will be joined there by Ivory Coast who beat South Africa 1-0 in the bronze medal match on Saturday.
In an even contest, also played in Windhoek, Rebecca Ida scored the winning goal six minutes from full time.
She pounced on a loose ball in the Banyana Banyana box from a corner kick, and slotted the ball home.
Excerpts courtesy if BBC