I have got jee main rank in genl category over 4 lakh and in obc-ncl rank 1,71,000, will I get admission at NIT or IIITs

It is not impossible, but you won't be able to secure a seat in any of the core branches

Regularly keep on visiting the counseling schedules. As ur rank is not very good for getting admission in certain top level colleges on the basis of merit. Meanwhile on the basis of ur marks in 12th u are elegible for getting admission in certain private colleges/institutes which provide better educ