It is not climbed for it's own, but mostly when collecting these 4000 m mountains. Corno Nero is in the "official list" of UIAA about the 4000 m mountains of the Alps and most authors consider it as an independent mountain. So go for it! Very recommendable - and popular - is the traverse along the ridge from Gnifetti hut to the Signalkuppe.
First ascent on August 18th 1873 by Marco Maglioni and Albert de Rothschild with guides Peter and Nikolaus Knubel, Eduard Cupelin and three porters (I wonder how this big party had enough space on the little summit!)
There is only one reasonable route from the basis. It's only 30 m or so, but these are much steeper than at the neighbor peaks that are only walk ups. Crampons and ice axes are necessary to cope with the 40 degrees steep slope of snow or ice. At the summit itself, a black rock of a few meters (3-5 m) is sticking out. The small surface of this rock makes it difficult to stand on the summit itself (especially when you're not climbing individually).
The little the mountain looks from west side from the Lis glacier - the steep the east side fells into the Sesia valley. So standing up there you have gained a spectacular viewpoint on a really high mountain.
No permits or fees whatsoever.
When To Climb
March to May with ski, July to September on foot.
Camping / huts
normally people sleep in one of the huts, so there is no need to do camping.
The original submitter wrote that camping was allowed near the Rifugio Mantova. This is surely the highest possibility outside the glacier. We saw parties that carried camping equipment onto the glacier. A possibility to camp on the glacier would be the hollow between Corno Nero and Vincent Piramide.
not guided is the Bivacco Giordano (4167 m) on the near rocks of the Balmenhorn
The bivacco is a shelter in case of emergency if the weather turns. But in the summer when the weather is fine there are always parties that sleep there. So the little cabin (6 places!) is often overcrowded.