Epic did say that you might in some situations forego normalmaps with Nanite and save disk space even though you have super detailed models so it DOES fit in this context.
Also, video games are used to take a high poly model and bake a normalmap corresponding to it on a lower poly model anyway so it might also be used that way. I think Doom 3 was the first game to show the technique?
With nanite normal maps are less required than otherwise because the detail is preserved in the mesh. You could make the argument that micro detail normal maps are still useful but those aren't always generated from the mesh. Especially if they are tiling.
Also, video games are used to take a high poly model and bake a normalmap corresponding to it on a lower poly model anyway so it might also be used that way. I think Doom 3 was the first game to show the technique?