You might even go one step further with this and define the JOIN conditions in a JOIN statement, which will significantly simplify the logic required in the WHERE clause.
Also, take note that TriggerTimeStamp is a DateTime value. You've defined it twice in the SELECT statement, once aliased as "Date", another aliased as "Time". These two columns will contain identical data. Unless you're going to strip/manipulate the data in the SELECT statement before sending to the console, you probably only need one of these values.
SELECT AS.ObjectName as Node, AS.TriggerTimeStamp as Date, AS.TriggerTimeStamp as Time, AD.Name
FROM Orion.AlertStatus AS
INNER JOIN Orion.AlertDefinitions AD ON AD.AlertDefId = AS.AlertDefId
WHERE AS.Acknowledged = 1 AND (AS.ObjectName LIKE %mpls% OR AS.ObjectName LIKE %bgp%)
ORDER BY AS.TriggerTimeStamp DESC