The answers to the following questions can help you decide between a new integration or a new object mapping:
Are you syncing data from/to a new "JIRA project"?
If yes, then it's best to create a new integration.
Do you need a different "integration type" (i.e. one-directional, bi-directional) than current integrations?
If so, then creating a new integration would be the best approach.
Will this new integration need a different "master application" than current integrations?
If yes, then it would be best to create a new integration.
Do you just want to sync data between an Accompa object and JIRA issue type while leaving the "JIRA project", "integration type", and "master application" the same?
If so, then creating a new object mapping would be the best approach.