That would work if your lathe is a metric lathe instead of Imperial. Best to check. The thread on the leadscrew is typically a British Standard Whitworth (BSW), left hand. Measure the TPI and you might be able to find a tap to make your own nut. You can also buy internal threading bars in the BSW pattern and screw cut it.
Another option is to buy some Acme LH threaded stock and make an Acme LH nut. The Emco BSW arrangement is smoother in use (yes, I tried this) and I would go with an Acme as a last resort.
I cannot recall what the nut looks like but the typical larger Emco lathes have two screws on the cross slide; one to attach the nut and one for a set screw that adjusts backlash on the nut. The nut has a slot at the rear and the screw, which has a coned tip, pushes on the end of the nut and collapses the material via that slot. It allows for zero backlash on an Emco lathe, something they are known for.