Not exactly sure what you are after but from my limited 3D experience with Maya you won’t get it to match properly.
This fortunately isn’t correct, both should absolutely be able to be matched… That’s kind of the point of colour management! If your colours aren’t matching in a colour managed workflow something is wrong with what you’re doing or what the software is doing and should be sorted out. In this case I think the issue is on your end so with some settings tweaks we should be able to make it work!
I don’t know what you (or anyone else who stumbles upon this) are already familiar with so I’ll just try to explain the whole process, pay attention to parts that concern and don’t concern you accordingly!
Firstly, I’d recommend using the official OCIO config for both programs. Maya 2022 comes with an ACES config but just to iron out problems and making sure our settings are in sync here I’d recommend downloading the latest version of the official one and setting that as your OCIO config in Windows > Settings/Preferences > Preferences > Settings > Color Management
over in Maya (nice labels Autodesk lol) and Edit > Preferences > Color Management
over in Natron.
In Maya’s colour management settings the rendering space should be ACES - ACEScg and the display space should be ACES.
Now that these configs are synced to the regular standard ACES config you should notice your output transform options are a little different. Pick the one for your monitor, it’s probably sRGB if you’re on Windows or Linux… If you don’t know you should really find this out before doing anything else!
In Arnold’s render settings files should be written out as EXRs and Color Space should be set to “Raw”.
In Natron make sure the read node is set to ACEScg as both the File Colorspace and Output Colorspace (it’s not in your screenshot!). In your OCIO Display node the Input Colorspace should be set to ACEScg, the view transform (which should be configured for your monitor as mentioned above) should be set to the same one that you use in Maya (or any other OCIO enabled application).
Remember that when using the OCIODisplay node you need to set Natron’s built-in viewer transform (located beside the exposure & gamma sliders) to Linear(none)
because Natron’s display transform settings are rather limited AFAIK and this only supports sRGB & REC709, once that’s all sorted it should give you no issues!
As always, if I’ve made any errors here please let me know and I’ll correct them
As a bonus feature request / gripe, I’d love to see more robust integration of OCIODisplay into the viewer, the user experience of having to always place the node above the viewer in the graph for anything other than linearized images with 709 primaries → sRGB is kind of clunky.