Regarding a SIM for the Nexus 6, guys, do not get your panties in a bunch over this. And do not impugn Sprint CS over it. No consumer has this handset yet, so it is not a pressing Sprint CS concern. You can compare to T-Mobile CS all you want, but that is not a fair comparison. T-Mobile deals with SIMs all the time. Sprint does not.
So, ask for a nano SIM (4FF) for the Moto X. Say you just bought a used one and need a new SIM. Done.
AJ