The German Kallipos Kalligraphie Shop shows this exact nib in a gray finish. The description (in German) says "Fine stroke, hardly flexible." The Worthpoint antiques pricing site includes a bottle-and-pen combination that includes another example of this exact nib. The Italian Tips and Tops blog has a partial photograph of this exact nib (in much better condition), but contains no identifying information at all. I believe that this partial photograph has been used on many sites. None of these sites show reference to the manufacturer.
I find no reference to any pen manufacturer named Nitor. However, the Latin word, "nitor," translates to "brilliance." Although there are many examples of dip nibs marked with NITOR as the central marking, some put the marking in quotes, and at least two manufacturers show both their company name and the word "nitor" on their nib. I conclude that the word is being used as a descriptor--like gold, bronze, plated, Durabrite or, simply, brilliant.
I have found several souvenir dip nibs in the shape of the Eiffel Tower. But the ones that identify the manufacturer are clearly different--by shape and by number of holes. I am stumped.
Therefore, since the only significant marking is the word Nitor, and in deference to the numerous dip nib collections that have identified numerous nibs as manufactured by Nitor, I will follow suit. Sigh.
There are no additional versions of the Nitor #0272 Eiffel Tower Pen in the Chappy's Nibs collection, as pictured below (gold-finish).
Click any image for a full-resolution photo: 1925 x 560. The image with the ruler is 2300 x 1196.