portainer/app/agent/components/node-selector/nodeSelector.html

<div class="form-group">
  <label for="target_node" class="col-sm-1 control-label text-left">Node</label>
  <div class="col-sm-11">
    <select class="form-control" ng-model="$ctrl.model" ng-options="agent.NodeName as agent.NodeName for agent in $ctrl.agents"></select>
  </div>
</div>