It doesn't look like there is a plugin/template to handle OTRS specifically for import, which means you'd need to leverage either the CSV or JSON import (assuming you are running a self hosted JIRA instance). You'll want to take a look of here:
Badges are a great way to show off community activity, whether you’re a newbie or a Champion.Learn more
Connect with like-minded Atlassian users at free events near you!Find a group
Connect with like-minded Atlassian users at free events near you!
Unfortunately there are no AUG chapters near you at the moment.Start an AUG