Hello Student, 

As per previous year opening and closing ranks of JoSAA,  a general category student need to have at least a rank around 30k-40k to get into NITs. 

Even with any other category there are quiet less chances to get any NIT or IIITs. 

One thing that you can do is try participating in CSAB special round if you want NIT only. 

Hope this will help. 

Feel free to ask any doubts.