The minimum Power Supply required for a GTX 960 is 400w. If yours is 430w, it should run it, but personally I'd recommend getting a better one. Your power supply should handle it, even under load, but it may put a lot of stress on the power supply. Depending on the brand, the reliability can be really low. If you do consider upgrading your power supply, I recommend quality brands like EVGA and Corsair. 600w+ should be perfect.
Again, your 430w Power supply will run it, but it can be a bit risky if it's a low end not-so-reliable one. Its not REQUIRED to get a new one, but it may be a good idea for a future purchase!
*UPDATE*
Antec is a pretty good brand. It should run fine. But anything above a GTX 960 will require a better...