Most eggs in one nesting box?

Depends on the number of hens laying in that coop.
They usually all prefer one or two nests no matter how many there are.

 

I had six that were laying all in one place, when I removed some eggs they all decided to go lay in another nest, and the same happen again after I took some out, when they went together to the third nest, one become broody, and amazing how the others went together to the first nest again, and again one became broody and amazing thing happen again, they went back to the other nest, it is almost as if they help each other to get their nest full to start their broody time.

 

I found 8 this morning in their favorite spot, it's not exactly a nesting box, but the eggs were well piled in there, if I had waited another couple hours, there would have been 11, as I found 3 more not even 2 hrs later.