can I get admission to nit through jee main paper 2 score ? what's the cut off for general male this year?

Jee Mains paper two is written by candidates who wish to acquire admission in Architecture related courses (mostly B.Arch) across NITs in India. You cant expect to get a B.Tech degree by writing paper 2.
As of now it is very hard to predict the rank or cutoff. The mark to rank factor keeps changing every year depending on the students performance. So you will have to go wait till the official result declaration by the results committee. You may refer to old cutoffs to see the trend:
https://engineering.careers360.com/articles/jee-main-cutoff