So you've already got the registry scanning enabled and pointed to that key, right? If so, give this a shot:
SELECT tblAssets.AssetID,
tblAssets.AssetName,
tblAssets.Domain,
tblSoftwareUni.softwareName,
tblRegistry.Regkey
FROM tblAssets
INNER JOIN tblSoftwareUni ON tblAssets.AssetID = tblSoftwareUni.AssetID
LEFT JOIN tblRegistry ON tblAssets.AssetID = tblRegistry.AssetID
WHERE tblSoftwareUni.softwareName LIKE '%Google Chrome%'
AND (tblRegistry.Regkey IS NULL OR tblRegistry.Regkey NOT LIKE 'HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Google\Update AutoUpdateCheckPeriodMinutes')
ORDER BY tblAssets.AssetName;