I have 74000 obc rank  can I get nit in spot round through girls quotas ?

Well their are chances that you can grab a nit but it will again be depending on which stream who want to choose. For some nit the cutoff is around 10k but for some it went up to 1 lakh depending on  the stream you want to choose.
For getting the seat in nit with that rank you might need to wait until the final round but you can get the seat regardless of which nit it is and which stream it is.