Nieder Kostenz is a municipality located in the Rhein-Hunsrück-Kreis district within the state of Rhineland-Palatinate, Germany. It functions as an Ortsgemeinde, which is a type of local municipality belonging to a larger collective administrative unit.
The village is part of the Verbandsgemeinde of Kirchberg. The administrative seat for this collective municipality is situated in the town of Kirchberg.