The purpose of Nexus Sprint Retrospective is all of the above, meaning that it aims to:
Plan ways to increase quality and effectiveness across the whole Nexus. The Nexus Sprint Retrospective is a formal opportunity for a Nexus to inspect and adapt itself and create a plan for improvements to be enacted during the next Sprint to ensure continuous improvement 11.
To inspect how the last Sprint went with regards to individuals, teams, interactions, processes, tools, and its Definition of Done. The Nexus Sprint Retrospective follows the same format and principles as the Scrum Team Sprint Retrospective, but at a larger scale. The Nexus inspects the aspects of the product development that affect the Nexus as a whole, such as the collaboration, the integration, the dependencies, the quality, and the value 22.
To complement the Scrum Teams' Sprint Retrospectives by using bottom-up intelligence to focus on issues that affect the Nexus as a whole. The Nexus Sprint Retrospective does not replace the Scrum Teams' Sprint Retrospectives, but rather enhances them by using the input and output from the individual teams to identify and address the shared challenges and opportunities 33.