Computer Configuration > Administrative Templates > Google Chrome - Default Settings (users can override) > Default search provider
Both
HKLM\Software\Policies\Google\Chrome\Recommended
If DefaultSearchProviderEnabled is on, then setting DefaultSearchProviderKeyword specifies the keyword or shortcut used in the address bar to trigger the search for this provider. Leaving DefaultSearchProviderKeyword unset means no keyword activates the search provider. Example value: mis