Final answer:
The nurse should listen for breath sounds over the epigastrium to confirm proper intubation tube placement.
Step-by-step explanation:
The priority action by the nurse that will assist in the confirmation of intubation tube placement in the proper position in the trachea is to listen for breath sounds over the epigastrium. When the tube is properly placed in the trachea, breath sounds should be heard over the chest and not in the stomach area. This indicates that the tube is correctly inserted and is delivering air to the lungs.