The nanking cherry needs 2 of itself to properly grow, but what if you have 2 different cherry types, will they pollinate each other?
It's not the same species as other cherries, but it is in the same genus. It may or may not be pollinated by other cherries. However, I think Nanking Cherries bloom a lot later than the other cherries we've had. So, that might be a problem. Ours didn't have a pollinator of the same species (but we did have a sweet cherry, which did not bloom at the same time) and we usually only got zero to a few fruits a year on the Nanking. I don't think it bloomed the same time as our sour cherry, either.
- Nanking Cherries are Prunus tomentosa.
- Hansen Cherries are Prunus besseyi.
- Regular sweet cherries are Prunus avium.
- Sour cherries are Prunus cerasus.
- Ornamental cherries can be from different species than listed above.
So, in short, I don't know, but I wouldn't count on it, due to the species difference. Blooming times are important to know, too. You might be better off getting two varieties of Prunus tomentosa.
You might consider not growing any Nankings and grow North Star Cherries instead. They're Prunus cerasus. I've read they may produce better and more abundant fruit. Nankings definitely aren't the easiest, it seems to me from my observations. So, that might be right. However, it looks like North Star is a sour cherry.
Sour cherries, Nanking and Hansen are supposed to be self-fruitful, but most sweet cherries aren't. Nanking didn't appear to be for us, though (maybe it needs a different kind of spring than generally occurs in southwestern Idaho). So, I'm not sure about that personally. Our sour cherry tree definitely produced a lot of fruit without another sour cherry tree, but we did have lots of other trees in the genus growing around it.