is there any solution to get the nmon data from the aix / linux servers an send them to a dedicated universal forwarder without a forwarder on every server?
I'm sorry not having seen your message before, and i'm happy you found your own answer.
For information, you will find within the App the full and up to date help page containing all required information, and deployment scenarios:
The answer to your original question is yes, people wanting to get nmon data indexed and available within Splunk can manage nmon data generating by their own process and simply make the nmon files available to the App by creating their own custom monitor.
Any nmon file placed in this directory (local directory, NFS share, whatever) will be converted and indexed by Splunk, and the performance data available within all interfaces the same way as if it would have been generated by the App itself.
This is the deployment scenario "Scenario 3: Manage NMON Data collected into centralized shares" fully described in help page.
Thank you for using the App, don't hesitate if you have any issue or question, and don't forget to rate the App 🙂
ps. Note an important release of the App has been published to day as of the version 1.3.3
Finding a resource that solved your question is as good an answer as any 🙂 I just put the link from your old comment and into your answer. Thanks for contributing!