Final answer:
The initial intervention by the school nurse should be to talk to the preschool teacher and obtain validation for the reported behavior.
Step-by-step explanation:
The initial intervention by the school nurse in this situation should be to Talk to the preschool teacher to obtain validation for behavior that the parent reports. By speaking to the teacher, the nurse can gather information about the child's behavior in the school setting and determine if the aggression is occurring consistently. This will help in understanding the factors contributing to the child's angry outbursts and develop a plan for intervention. It is important to gather information from both home and school to get a complete picture of the situation.