I don't know about a precise Scotia ATM at the airport I do know there are a few ATM's across from the taxi stands so look to the left as you exit Customs and get thru the Timeshare Shark Tank.

There is a Scotia Bank in Plaza Peninsula, about 10 minutes or less going South from the airport.

There is a Starbucks on the corner of Plaza Peninsula, take a right there and the Scotia Bank is down the driveway on the RH side.

Pesos are the National currency, they are much more widely used and appreciated in Puerto Vallarta.

Hope this helps, hope the info isn't too late for you. Enjoy Vallarta !