Final answer:
After a supratentorial craniotomy, the child should be positioned on the inoperative side with the head elevated 20 to 30 degrees to minimize intracranial pressure and aid in recovery.
Step-by-step explanation:
The nurse should place a 10-year-old child on the inoperative side with the head of bed elevated 20 to 30 degrees after a large tumor has been removed through a supratentorial craniotomy. This position aids in decreasing intracranial pressure, allows for better venous drainage, and helps in reducing swelling. It is crucial to monitor the patient's neurological status as well as vital signs carefully during the postoperative period to ensure optimal recovery.