Dear Student ,

The teaching methodology in IITs and NITs are not too much different . But , with the view of syllabus and referred books .. there may be a little difference as recommended  text books can't be same in all  colleges . May be the reference books of some IITs can be a text book for any NITs . So, if you go in library .. most probably all required books will be available in both NITs and IITs so that you can issue your preferred books anytime .

Hope you understand !