The Nuptse might work if you were heavily layered and the temps were moderate, but on the other hand, I wore it for a short walk to the beach tonight and it's 60, but that's just me. You would also need a fleece under it, a heavy base layer, and of course mitts or gloves (not just liner-style gloves), a balaclava and insulated or fleece pants, too. For just sitting around, if the temps are below freezing, even with the fleece and all the rest, I think the Nuptse or anything like it would be inadequate unless you have the body type of a polar bear.

The Nuptse is nowhere near the parka my Baltoro (predecessor of the Himalayan) is, so using one as your primary winter insulation would be a big mistake if the weather turns for the worst. One more thing I thought of-the Nuptse is ripstop nylon, the Baltoro is Goretex Dryloft and the new Himalayan is Windstopper, big difference there as well. Big difference in price, too. The Himalayan retails for $600. I paid nowhere near that for mine on eBay, so if you are contemplating getting something like it, look around first.

Here's a photo of me wearing it in Yosemite on my trip with Jim and Steve-