Which officer follows directly under the Executive Officer in the chain of command?

The officer who follows directly under the Executive Officer in the chain of command is indeed the Officer Candidate School/NSI Course Supervisor. This role is specifically designed to manage and oversee the training environment of officer candidates, ensuring their education aligns with the standards and expectations of the Navy. The Course Supervisor is responsible for the operational aspects of training and directly reports to the Executive Officer, thus forming a crucial link in the chain of command.

The other roles mentioned, such as the Class Officer, Class Chief Petty Officer, and the Commander of the Naval Service Training Command, play important functions within the broader context of officer training and operations. However, they do not fit directly beneath the Executive Officer in the hierarchical structure as does the Officer Candidate School/NSI Course Supervisor. Understanding this chain of command is fundamental as it underscores the relationships and responsibilities inherent in Navy leadership and educational processes.