Silvenon showed how this works quite well with that trigger above.
Just to help you with how the "Order" action works; Each ability has a "Orderstring", you can find this in the Object Editor:
Text - Order String - Use/Turn On: <"a orderstring here">
The orderstring for, say chainlightning, is "chainlightning", but it is not always that simple.
The orderstring can be changed to another one, example, you can change the chainlightning abilitys' orderstring to "cyklone". But it always has to have the orderstring of an ability which has the same targets. For example, a point targeted orderstring (ex: blink) cant be used for a unit targeted ability (ex chainlightning).
So the only thing you have to worry about is that the trigger uses the same orderstring that the ability you want to use have.
Maybe you knew all this, wasting my time then...
