The chances are pretty dim since the past trends show that the NC OBC waitlist movement went till 400 and although last year it went on till 480, to be on the safer side make some back up plans.
You need to realize that waitlist movement is reliant on so many factors. It's simple maths; IIMs have nearly 5000 seats and BLACKI is the first 5 choices of almost all the students.
We all know that the selection process for admission to the IIMs is rigorous and only a small fraction of students convert their first preference in the first shortlist and where do you think the remaining students are at for the time being? They take admission in their backup colleges and IIMK is a popular choice among top percenters, so you need to wait patiently but don’t anticipate too eagerly.