Well, that was my mistake, as a nurbs object it's not so simple, the quick fix to this is to convert to SubD

Modify>convert>NURBS to SubD

Use polygon proxy mode and choose faces.

otherwise, you could create an image in a photo editing sofware (photoshop or whatever) placing the 2 pieces (night/day) together (thus allowing to you make the shift smoother with the tools in that sofware....)

then apply the texture to the sphere and adjust the settings in the place2dtexture node as necessary.

REMEMBER: when applying a texture to a Nurbs sphere keep an eye on the seam, it can cause some rather tricky problems