Hi,
There is no way to instantiate the tile map data prefab, so basically it will need to be generated at runtime. You can call force build if you want, which will do what it needs to. It isn't super fast to instantiate like that but is necessary as Unity will not save meshes, etc. in a prefab.
The alternative, more efficient method is to save the tile map chunks as scenes, then LoadSceneAdditive. Once you have the built tilemap, you can simply Instantiate the render data object instead of the tile map, it should work as long as the master exists somewhere.
You should consider caching all of this on startup and not Instantiate large tile map chunks at runtime.