M.Tech CS at ISI Kolkata isn’t just for CSE graduates. The student crowd includes students from all engineering streams. So, in the first year, ISI encourages students from non-CSE backgrounds to learn coding and study computer science courses. While CSE students are encouraged to take Mathematics courses such as Algebra, or Probability.
Second year course curriculum can seem a little boring for students with CS background. As the major chunk of the curriculum includes Algorithms, Networking, DBMS, etc. But you should use this opportunity to brush up on these subjects. You will also have the option to do research work, during the course tenure. Pursuing a research project can be really helpful if you are interested in doing a Ph.D. or an internship afterward.
In the second year, you will be allowed to choose a course of your choice. Try to take a subject that is relevant to your thesis work. The coursework in the third year can get extremely hectic, you will have to work on your thesis, start preparing for placement or PhD, and work on five subjects.
The curriculum of M.Tech C.S. in ISI Kolkata is quite basic. As much as I know, the lengthy hourly classes and other research work make it quite boring at times.
So, work hard from your second semester. I hope this helps you in understanding or at least have an overview of the curriculum at ISI Kolkata. But, I would personally suggest ISI Kolkata especially if you are planning to do a Ph.D. from here.