Yes its the MOI interview.
They are inviting 2020 applicants now, so you maybe called as stated by your SB Officer.
The usual wait time from NIA to MOI interview is 18 months but it varies considerably for many applicants.
Standard wait times include 18 - 30 months
Getting worried in case the documents go missing somewhere. It will be too much of a pain to start all over again -
Thats not the case, all the documents are handled responsibly by the SB Police, NIA, MOI.
I have never heard that the Ministry lost documents of a particular applicant, So dont worry in this regard.