The only thing you did was loading an image into the uv editor and adjust where exactly the polygon is in the uv space. You have to create a material for your object so that blender knows what to display. Easiest would be to import a mesh from NWN and look how it’s done in the shader editor.
It’s a bit complex to describe every step here, especially if there are hundreds of videos explaining that in far more detail. Just search a tutorial about materials on youtube.