Hello,

there might be change in exam pattern but that won't effect to the NIT or IIIT selection criteria. they intake candidates on the basis of rank which is calculated from many factors and the most important factor is percentile you score in JEE Main. Your percentile will get affected by your score in your entrance exam.

In other way even your percentile is higher there will be many candidate with higher percentile or same percentile as you and you will  left behind as your rank will be high drastically.

Lets assume if you got percentile 99% there will be around 5k-10k students with 99.0-99.9% percentile. Then your rank will be near to 6k-11k. if so you will not get NIT or IIIT. so it totally depends on how many candidates are before you.

Nothing to worry just give your best. in addition a rank below 2Kis considered to get an admission into NIT or IIIT easily through counseling.

Hope it helps!