It's difficult to predict with absolute certainty  whether you will get a seat in an NIT through CSAB counselling with a rank of 11605 in the EWS category (Andhra Pradesh domicile) for the following reasons:

The number of seats available in NITs for EWS category students is limited. This makes competition high.

Cut-off ranks for CSAB counselling can vary each year depending on factors like the number of applicants, difficulty level of the exam, and seat availability. Since this is the first year of CSAB counselling, there's no previous data to definitively predict cut-offs.

It's still beneficial to participate in CSAB counselling. Even with a higher rank, there's a chance you might get a seat in some NITs or other institutes participating in CSAB, especially for branches with lower cutoffs.

I hope it helps!