What is the concentration of a titration curve of 65 ml of HNO3 with 0.800 mol/l KOH

First, we can't draw plots on the board.

I don't know what you mean by a "concn of a titration curve." The pH at the equivalence point of HNO3 and KOH titration is 7.00 and the equivalence point occurs at
mLHNO3 x MHNO3 = mLKOH x M KOH
The concn of the KNO3 at the equivalence point is moles HNO3/total volume(in L)