Hello Aniket,

The criteria for getting admission in NIT is to get desired rank cutoffs and you must get 75 percentage in CBSE Boardd and you should be in top 20 percentile of your state boards. Since you have mentioned that you are from Bihar Boards, if your percentage lies in the top 20 percentile range and you qualify JEE Mains with a rank that lies in the cutoff range for a seat in NIT, you would be eligible to take admission in NIT. Please note that with your boards percentage, that is 70.6 percentage, you have very high chances that you are in that top 20 percentile of Bihar Boards. 

All the best!