I have got a rank of 28000 in JEE Mains my score is 145/360 in General category but I have failed to get 75% in my boards so can I get NITs?

No but you can drop a year fir that

No you may be eliminated in the counseling. However I suggest you to attend them, if something can be done. You may have applied for different state CET. Well its late now to apply for them.

You can also check private colleges website if admission is available in them, however some conduct their own entarance test. If you dont have any problem and get a good private college I will suggest you to take admission in it because a major change is being aspected next year...

All the best

To get admission in NITs you must secure 75% marks in your boards exam or you should be in top 20 percentile.

You can try in colleges other than NITs/IIITs and GFTIs

All the Best!!