As you said you have scored 73 percentile in JEE MAINS and you also belong from ST Category means that will be beneficial for you a lot. Cutoff for ST Category this year was 44.3345 means you have cleared the cutoff with very good marks and in Boards to you have scored 64.4 percent but for ST category you want minimum 70% Score in Boards. Unfortunately, you are not qualified for the NITs. But don't be sad you can check various other colleges and explore other colleges too at JEE MAINS College Predictor.

If you want admission in other colleges on the basis of JEE Mains Marks you can choose JEE MAIN PREDICTOR as being provided by Careers 360 only at a very nominal price. You will be provided with all the details of the colleges with the best branch. You can use that it is really very good and you can check and explore various colleges and choose the best college.

https://engineering.careers360.com/jee-main-college-predictor?icn=jee-main-clgpd_landing-page&ici=prediction-section_c360-home