@Joseph_Culbert I’ve worked with files from several solidmoders over the years and they all seem to export assemblies as blocks and nested blocks. I think the only way you could go the other way would be to convert each named body\object in Rhino into a block then select all blocks on a layer and create a block with that layer name containing all the blocks.
What you’d get in Fusion would be a component using the layer name then sub components with the same name as your objects. I’m pretty sure BOMs in Fusion only work with component names not body names anyway.
Mark