Exporting a Scene from Unreal for Nu - bryanedds/Nu GitHub Wiki
Follow this video, albeit with one exception: choose to export as .gltf so that all the textures get exported (unlike with FBX, which just results in only the mesh being exported.
https://www.youtube.com/watch?v=D2KWFnhqyjs
Here are the export settings I'm currently using -
Of course, there's still more work to do with the output, such as swapping the color channels like so -
R <- G
G <- B
B <- R
...renaming files as appropriate, and setting alpha values of non-albedo PNG files to 255 and saving as TGA or TIF format since PNG is by default reserved for 2D images.