Though i am not an expert, but here is what i think.
Based on your profile,
For Cornell, if you going for regular 2 year MBA, Your score might be a non starter as the competition is really high for Indian applicants. If you have time i would suggest to retake your GMAT and try to score atleast average GMAT score ,which is 710 for Cornell.
While Cornell has a STEM designated MBA program , its a relief from Visa point of view. So you can explore. Besides. Cornell is well known for its Tech and Finance industry post MBA. So check your fit against your profile as how closely your goals matches. Majority of the undergrads before MBA are in from Business background and hence the pivot to Finance Industry post MBA. Second goes in to Consulting. So you need to check with your Industry type as per your Short and Long term goal.
For NUS ,it is a decent score, if your profile has good elements. Based on what your wrote, you might have some good EC's but you need to show leadership initiatives too for NUS.
Overall, your geography matters as far as the recommendation is concerned. So, good luck with your applications.