I get away with more, it seems that they all like two in particular and I wind up with 8 or 9 in that box, while the rest have five or 2 or... I have actually watched them staring each other down, waiting to get their turn in that particular box, lol
Oh my goodness no!... NOT 1:1 they'll fight over the same nest, or two nests... depends on how many you cluckers you have. 30 hens, 4 nests, is enough for me, though, many people have 6 nests just because that's normal. I have ... well 4.5 nests, three regular sized ones, and one 'double wide' nest. Most like the double wide one, (or close to it... maybe not quite an actual double)
I have, uh, 13 hens that are laying right now and 3 nest boxes in the coop (and a couple more outside), they use all 4 some days and on others only 2. I tell you, there cause quite a stir when they want to lay and the box they wish to use is occupied...yow, they could wake the dead
Still, its more a preferential thing for your hens, just 'cause you have more boxes doesn't mean they'll use them.