Since you have not mentioned any particular branch, I assume that you are getting to choose from all the branches at both institutions. Both the colleges have their own pros and cons.
Being a student of NIT Surathkal, my brother has often talked about its greatness.
Campus:
Academics:
Faculty:
Coding Culture:
Location:
Overall both the colleges are equally good. But NIT Surathkal has a clear edge over NSIT in various aspects.