Etruscan League was basically alliance of city states so it hardly is able to such thing as Romans were unless one of them take all others. And even then expansion would be unlikely at least with same way as Romans did. Etruscans were ratherly merchant people not so much militaristic ones. So more likely is some settlements to useful places.
Honestly, even that is pushing it. From what little we know of Etruscan internal history the Toscanian Dodecapolis, which is what is usually called the ''Etruscan League'' and covered Etruria proper, was less of an actual alliance then something closer to the Amphictionic League in Greece say, an organization put in place for dealing with common religious interest and the like. The Etruscans of Campania further south seem to have had a similar organization in place but, likewise, without more to it.
Sure, some cities built themselves little spheres of influence every now and then but none of them appear to have been big or stable enough to truly change things in the long run...
If you want the Etruscans to become an expansionist power your best bet is the third area of strong Estrucan settlement, Padanian Etruria in the north. From what little we know (again, Etruscan internal history is fuzzy) their own Dodecapolis started as something similar to what was going on further south but it wound up evolving into a loose confederation to better face pressure from their Celtic neighbors. Since we don't know a ton of what was going on in the area in this era I suppose there is no reason why we couldn't imagine a scenario where it further evolved into something more centralized and get to a point it had both the strength and the inclination to send forces south to conquer their brethren while still holding the Celts at bay. From that point then you can have them expand further.
