This does indeed sound as though you are being considered for the ISR (Immediate Scholarship Reservation). Before reading the rest of this, it's important to note that I am about 6 months into retirement, and while that does not sound like a long time, things change pretty fast in the world of NROTC and scholarships. With that being said,
The person who will be doing your interview sounds like the Commanding Officer of the NTAG (Navy Talent Acquisition Group)........please do not refer to him/her as a Commanding "Chief" during the interview or any email correspondence.
That interview could be just to validate you are the selection, but several NTAGs will conduct multiple interviews and select one candidate for the ISR. And they usually will not tell you until they make their selection decision. Here is the potentially tricky part. Since you have already conducted your required officer interview, that interview write-up is already entered into the database. IF you think you did a fantastic interview for the ISR, and IF the NTAG CO is so inclined, you can request that the interview be submitted in place of the NROTC interview, which is on file. Some NTAG CO's automatically do this, but some are brand new to their position and may not be aware that they can submit an interview in the same way that a PNS can. To be clear, the NTAG CO can reply that he/she is only conducting a brief interview to determine if you are a selected for ISR rather than doing a formal interview, but if they are willing to say good things about you to the NROTC board, it will have a little more weight behind it because of the seniority of the interviewer.
Hope that isn't more confusing than it is helpful. One final note......being selected at the NTAG level can mean you sit in the big queue of applications waiting for final review by NSTC. I cannot recall any ISR selection ever being overturned, but there is a final review by the Naval Service Training Command. Best of luck to you!