I upgraded to Nessus v7 and I have not received a single scan result via the Splunk add-on for Tenable. So I would say at this point it is broke. However reading the Nessus documentation on v7 it reads as follows: (please note the sentence in bold). So I currently have a ticket in with Splunk and they are looking in to this issue.
Access to the API for scanning is removed. Nessus Professional is designed to perform scan functions through the UI only. The scan API capabilities will remain operational through December 31, 2018, provided that users do not opt in to the v7 features. We recognize that many users export the scan data to create their own reports, so we have retained those capabilities in all versions of Nessus Professional, including v7. The scan API capabilities removed in Nessus Professional v7 are available in Tenable.io Vulnerability Management for those seeking additional automation and management capabilities.
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