Enabling Output:Variables Output:Variables on the Variables tab of OpenStudio does not allow you to request a specific Key Value Value (i.e. the specific name of the node you want in this case, cf E+ I/O reference Guide here), case), so you end up with all nodes being reported, but that includes the one you want. (By clicking on the chiller outlet node (or any other node) in OpenStudio on the HVAC tab you see its actual name in the right pane).

If you want to avoid having all nodes being reported, you'll need to use the ruby bindings or an OpenStudio Measure, for eg:

• Add Output Variable
• output_variables_from_csv: you can use a CSV file to specify the Output:Variables you want, including potentially using a schedule for reporting (eg: report only one week every month) to avoid having too large SQL files.
• enable_detailed_output_for_each_node_in_a_loop: allow you to enable reporting for nodes in a specific plant loop: either all nodes (supply + demand nodes), or supply side only

(disclaimer: I'm the author of the last two)