Final answer:
The incorrect nursing intervention for a 5-year-old boy with chickenpox is providing alcohol baths as needed.
Step-by-step explanation:
The incorrect nursing intervention for a 5-year-old boy with chickenpox is providing alcohol baths as needed. Alcohol baths are no longer recommended for chickenpox because they can irritate the skin and lead to complications. Instead, it is important to keep the child's fingernails short to prevent scratching and infection, monitor fluid intake and output to ensure hydration, and administer antipyretics as ordered to reduce fever.