I had a single tree blooming behind the barn for 20 years, no other tree close enough, so blank nuts for 20 years. They are not self fruitfull…well, an occasional tree, like 1 percent of them, but, largely, self barren. There is a tree outside Harrow, Ontario, that sets nuts on its own pollen, but the seedlings grow slowly and the survival rate is not good past 5 years or so.
This year I had 3 trees blooming on the home place, and hand pollinated the one behind the barn…and am expecting a few nuts where I could reach burs to pollinate.
I’m in the Gulf of St Lawrence, so nutfall will be later here, sometime in October, going by last year.
One of my trees is from a very inbred seedlot, and is male barren, pure american, but doesn’t pop out many anthers, and the 3 or 4 anthers it does pop out have only set 2 nuts by hand pollination…no creamy dust on the fingers either from handling them.
The second tree from that seedlot had 3 catkins this year, all nice and fuzzy and shedding 
Someone in zone 5 was asking about chestnuts for there…if you are coastal, get nuts from a coastal area, as inland seedlots here tend to wake up when it’s suddenly plus 5 to plus 8 in a January or Feb thaw, then, within 24 hours, it’s minus 15 to minus 25. (degrees C)
When that happens, they wake up, lose hardening and just never leaf in the spring.
I’m 5b/6a, depending on the year.