Not really sure what you mean by “name every instance object the same name as prefab”? Do you mean that when baking it out to a prefab, to have a way to change the name of the instances?
The name of the instances are made by combining the name of the output node in the instancer with “Instance_” and an integer to uniquely identify the instance. An example would be “object_merge_Instance1” for the first instance.
If you do want to change the names, you can either change the name of the output node in the instancer, or in Unity, have an Event callback when Cooking or Baking to change the name of the generated gameobjects (see
https://www.sidefx.com/docs/unity/_assets.html#Assets_AssetInspectorUI_Events)