So, I'm sitting here in Cabo with my N6 on Verizon, and I have no service. Do I need to do something with the phone or Verizon prior to leaving the U.S. in order to make calls?
Assuming you didn't get a local SIM in Cabo - and still have the Verizon SIM in your phone, did you get international roaming enabled on your phone? If not, that may be why.