Would a two year gap affect my chances of getting into NITIE?

No, a gap of two years will not hamper your chances of getting into NITIE. It is a common thing, actually. Students who are preparing for competitive exams often take breaks.

Imagine you are the interviewer and you have two CVs in front of you. One CV has a gap of two years and the other one does not. It is up to you who you want to select. The general answer will be the fresher.

But it depends if a two-year gap will have any effect on getting admission. It is not the only factor that determines admission, though. If you perform well in your GATE/CAT exams, have an admirable track record in academics you will have a good chance of being selected. A good experience in work also goes a long way in solidifying your chances for admission.

You have to come up with a reason for the gap in your CV that is reasonable enough to the interviewer(s). Convince them that the purpose for taking the gap is reasonable even if you are preparing for the competitive exams. Because at last honesty and confidence counts.