Use nanite fallback mesh for procedural foliage

In my game I have a boulder that has around 1M triangles and 500K vertices.

And I think that the fallback mesh, with only 10K triangles and 5K vertices doesn’t look too far from the original mesh. So, I wanna use the fallback mesh instead of nanite.

I’m using procedural foliage. How can I use the fallback mesh instead of the original mesh?