Hello,

If you are aspiring for top NITs, your rank should be less than 10,000. However, newer NITs accept candidates who are above 50,000 rank in JEE Main.

It also depends on the reservation policy of the respective institute.

• The students scoring more than or equivalent to JEE Main cutoff marks along with scoring minimum 75% of marks in their Class 12 board exams (65% for Reserved Category candidates) will be considered as qualified for getting admission in NIT through JEE Main.
• For getting admission in NIT Colleges, the candidate should rank within the opening and closing ranks of different undergraduate courses offered at NITs and IITs.

As IITs and nit are top rated Institution of India you markes should be good enough too.

https://engineering.careers360.com/articles/jee-main-cutoff

You can refer to this link for more information about cut-off ranks.

Hope this helps!!