Given this information, I believe that you could be looking at an ATAR around 95-96. Your performance in English Advanced and Legal Studies seems favourable and is likely to make a positive contribution to your ATAR. The same can be said, although to a slightly lower extent, about your performance in Mathematics Extension 1 and Chemistry. Maintaining and improving this standard of performance will require you to keep preparing for your HSC exams to the best of your abilities (with an emphasis on your Mathematics Extension 1 and Chemistry exams).
Mathematics Extension 2 seems like your lowest performing subject and could be limiting your ATAR, especially given the fact that it contributes 2 units towards your ATAR and that you are taking 10 units in total, meaning that it will definitely count towards your ATAR. Because of this, you may wish to consider placing additional focus on your preparations for your Mathematics Extension 2 HSC exam so that you can maximise your performance in this subject and hopefully increase your chances of achieving your ATAR goal. Depending on your performance in your respective HSC exams, you could potentially exceed this estimate.
I hope this helps!