Hello aspirant, 

All the candidates who have qualified Jee mains can sit for csab counselling to get vacant seats whichever is left, 

But we can not assure you that you will definitely get a seat, if you have good rank then you can surely get otherwise chances are less, because seat allotment is done on the basis of all India rank. 

Hope it helps. 

Dear aspirant,

The CSAB round is a special round for NITs IIITs and GFTIS . The central seat allocation board (csab) special round is for the left over seats at the above institutions mentioned. All jee qualified candidates are eligible to take part in this round.

https://engineering.careers360.com/articles/csab-special-round-for-nits-iiits-and-gftis

Kindly copy and open this link to see all details about the CSAB round. Yes you have qualified

all the best