Hello,
We can say you will most probably able to secure a seat in Barch at top 10 NITs, but we can't say in which round that might happen. Seat allotment is completely subject to the competition and students filling their options, which we can't guess how it might turn out. The point is you will be able to get a seat in top NITs, try till the last round, there might be a chance to definitely get into a better one. For more information about closing ranks of various NITs go through the link below-
https://engineering.careers360.com/articles/jee-main-cutoff-for-b-arch-b-planning