We had a nice ground-level* nesting box with a couple of fake eggs and thick layer of leaves in it, which the chickens ignored in favour of the poopiest corner of the coop (I'm flattered that they think it's still pleasant enough to lay an egg in, but... no. Stop that). So I stacked a second box on the first, and lined it with newspaper and a thinner layer of leaves to mimic their beloved coop. It seems to be working so far.
Edit: One of them liked the coop enough to get back into it after I closed off the two chicken-sized entrances. I don't know whether she got in through the propped-open top or through the space where the front of the droppings tray used to be, but both of them would have been awkward.
*Ground-level for the chickens, much higher for us. The run is next to some steps.