What feature of AWS CloudFormation will accomplish this?
Change sets
Nested stacks
Stack policies
StackSets
Explanations:
Change sets allow you to preview changes to a stack before applying them, but they are not designed for deploying a template across multiple accounts.
Nested stacks allow you to break down large templates into smaller, reusable templates, but they are not meant for managing stacks across multiple accounts.
Stack policies control what actions can be performed on a stack, but they don’t provide functionality for deploying a template across multiple accounts.
StackSets allow you to deploy and manage CloudFormation stacks across multiple accounts and regions from a single CloudFormation template.