NEMA frame-size standards only define the dimensions of the mounting faceplate. To figure out if it is compatible, you need to know the electrical specifications of the motor.
When in doubt, it is always better to err on the safe side and use a lower current!
When calculating the torque required for your project, be sure to allow extra torque required for acceleration and to overcome friction. It takes more torque to lift a mass from a dead stop than it does to simply hold it up.
If your project requires a lot of torque and not much speed, consider a geared stepper.
For other motors, check the motors spec sheet if available.
If you don't have a spec sheet, check Jason on reverse engineering the stepper wire pinouts.
Next, check the current rating. Most stepping modes energize two phases at a time, so the current rating should be at least twice the current per phase for your motor.
* This applies to constant voltage drivers. For chopper drive controllers, check the instructions for your controller.