Hi Ian, Up-state NY here and winter is snowy. Also I work construction and frequently drive dirt roads and on job sites.
My NV200 is a 2015 with 20K and I have driven 1 and a half winters in this van.
Also I am a careful driver, I don't like to hear or feel my vehicle complaining about road conditions so I don't mind taking my time.
I can only compare my experience with a FWD VW Passat I was driving which handled itself fairly well in these conditions.
Having said that, the biggest issue I face with the NV200 is the ground clearance. I have to pay attention to the ground conditions when I am driving on job sites.
In the snow the NV200 has it's limitations. I am careful when a storm is blowing and the possibilities of the plows not keeping up, but I think in most cars one would have to careful too. I have to say I felt more confident in the Passat.
However, job site access and job sites where I can pick my way in and take my time in the snow the NV200 has done well. I think that the skinny tires actually dig down into the snow for grip rather than sliding along like a wider tire might. Of course you are limited with the low clearance, not many cars can push snow with their bumpers!
Plus I found that the CVT has an interesting quality. If you are in a low traction situation and stopped I step on the gas slowly raising the revs until the tires begin to turn. It feels like the CVT delivers a nice combination of torque and power to the tires. If they spin I can put some sand or gravel under them and try again. As you know once you get moving you can usually keep moving and that technique has helped more than once.
Oh, and I don't have snow tires, not that I don't need them, I'll be looking to buy some soon, but so far my experience above is with the tires that came with the new van in 2015.
Over all, I don't really give winter driving much thought and the daily dirt roads treks pass with ease.