Would a stepper motor driver chop a high current to its max allowable limit efficiently everytime?
You can't increase the input current, the driver will sink the needed amount which in your case is 750mA (per phase IMO, so 1.5A total). You have to provide a stable voltage source that  can source at least that amount of current, higher is better.

Q: Will the chopper driver limit the current efficiently anytime?

A: Well, it depends on the setpoint speed and supply voltage. The motor is always producing back EMF voltage - generator mode. As long the supplied voltage is greater than motor BEMF voltage, then it will be able to maintain the current at setpoint level. At higher speeds the motor BEMF voltage becomes high, almost the same as supply voltage. In this situation the potential difference is zero and it is impossible to feed the motor with such current. The motor looses torque at high speed. Higher voltage -> higher max. motor speed.