Payment for Ecosystem Services (PES) is not only a prominent, globally promoted policy to foster nature conservation, but also increasingly propagated as an innovative and self-sustaining governance instrument to support poverty alleviation and to guarantee water, food, and energy securities. In this paper, we evaluate a PES scheme from a multi-scalar and political-ecology perspective in order to reveal different power dynamics across the Water-Energy-Food (WEF) Nexus perspective. For this purpose, we analyze the PES scheme implemented in the Hidrosogamoso hydropower project in Colombia. The paper shows that actors' strongly divergent economic and political power is determinant in defining how and for whom the Nexus-related water, food, and energy securities are materialized. In this case, the PES scheme and its scalar politics, as fostered by the private/public hydropower alliance, are instrumental to guaranteeing water security for the hydropower scheme, which is a crucial building-block of Colombia's energy security discourse. For this, the water and food securities of the adjacent, less powerful communities are sacrificed. Examining the on-the-ground politics of WEF Nexus is key to understanding their impact on equitable and sustainable governance of water, energy, and food in the everyday lives of millions of resource users. We conclude that politicizing the Nexus can help to trace both the flows of resources and the flows of power.