can i use a Darlington ULN2803 Driver to run my NEMA 17? If not what driver would you use? (The steppers will be powering wheels that are moving about 2-3 lbs of weight)
Yes, or no. That all depends on your motor - 4, 5, 6 or 8 wire? Winding impedance? Current rating?
The key parameter is torque at the motor, not weight on the axle, the bearing takes the weight, not
Steppers are an inefficient means of traction, an order of magnitude more power hungry than
a DC motor for most loads.
You need to post a link to the datasheet for your stepper motor so we can see the technical details. There are hundreds of Nema 17 motors.