Hi,
Someone else better than me with Nanite import found using the latest version of source ue5-main or now called 5.0 on Github works.
The Datasmith files DO NOT WORK UE5 EA2 BINARY. It was August 2021 (at least 8 months ago🤣]
Here is what happened to DataSmith for Revit 2022.
The Revit problem was raised and fixed in
Can´t enable nanite for more than 12287 assets
They describe how it was fixed in
Revit 2022 Datasmith
The code has now been installed in the latest version all the Datasmith importers have been updated and fixed.
see source build tutorial
Visual Studio 2022 builds and latest version and runs UE 5.0