Nienstädt is a municipality in the district of Schaumburg, in Lower Saxony, Germany.

Nienstädt lies on the northern slopes of the Bückeberge between Bückeburg and Stadthagen on the B 65 federal highway.

While Sülbeck and Nienstädt are bisected by the B 65, Liekwegen runs along the Bückeberg as a ribbon village.

Wackerfeld and Meinefeld lie in open country north of Nienstädt.

Neighbouring communities (clockwise) are the towns of Stadthagen and Obernkirchen and the village of Helpsen.