Final answer:
The nurse's priority action is to dry the newborn immediately following delivery.
Step-by-step explanation:
The nurse's priority action after assuring a patent airway for a newborn immediately following delivery would be to dry the newborn.
Failing to dry the newborn can result in cold stress which is the greatest risk to the infant's safety. Cold stress increases oxygen demand and can lead to respiratory distress and hypoglycemia.
Administering phytonadione IM, documenting the Apgar score, and applying identification bands are important actions, but they are not the priority in this situation.