Was the coolant at proper level before this happened???? If the coolant resorvoir was empty the system may have gotten air in it causing the problem. When and if you do change thermostat most say to get the factory thermostat from either Ford or Nissan they are heavier built and some people have had trouble with aftermarket. The thermostat could very well be the original one and sticking.
Also make sure there are not any hoses leaking, there are a number of hoses behind the plenium.