what is the the score I should gain to get an admission in any of the nit?

JEE Mains is the entrance examination for admission to NITs, IIITs and CFTIs across India. So to be able to take admission in NITs, you should meet JEE Mains criteria and in additional, the specific criteria for NITs, IIITs and CFTIs. For admission to NITs, you should have secured a minimum aggregate of 75% in your 12th with Physics, Mathematics and Chemistry or any vocational subject. It is 75% for General Category and 65% for Reserved Categories. Or you should be in the top 20 percentile in your Class 12th examination. For more information, please read our article: https://engineering.careers360.com/articles/jee-main-eligibility-criteria

Regarding the score, you haven't mentioned your Category. Neverthless you will need atleast 95 percentile and above for a seat in NITs if you belong to General Category and atleast 90-92 percentile of you belong to Reserved Categories. For previous year cut offs in NITs, please visit our page: https://engineering.careers360.com/articles/jee-main-cutoff