Computer Configuration > Administrative Templates > Google Chrome - Default Settings (users can override) > Startup, Home page and New Tab page
Both
HKLM\Software\Policies\Google\Chrome\Recommended
Setting the policy to Enabled shows the Home button on Google Chrome's toolbar. Setting the policy to Disabled keeps the Home button from appearing. If you set the policy, users can't change it in Google Chrome. If not set, users chooses whether to show the Home button.