My general rank is 105468 and ews rank is 12517 in jee mains 2019. Can I get nit

Almost certainly. Since the government has augmented the seats in IITs, NITs & GFTIs by 10%, to accomodate the new reservations for economically weaker sections. However there is a chance that there may be a huge reshuffle in JEE Advance examination & many who failed to perform great in JEE Mains may do well in JEE Advance, leaving the high ranking JEE Mains students stranded to occupy seats in NITs & GIFTs. In my opinion even many autonomous govt./private colleges are now performing at par with NITs, hence there is no point in jumping in to the rat race.