It depends on what kind of nerve conduction test you're scheduled for. Some test the peripheral nervous system: whether the nerves in your limbs are working properly, are transmitting signals from the limbs to the spinal cord (and then to the brain). Other nerve conduction tests will test the central nervous system...whether signals are being properly transmitted from brain to spinal cord, and then to the rest of the body.
If there is a problem with the peripheral nervous system, it's not likely to be caused by having MS. If there is a problem with the central nervous system, MS is one candidate for the cause.