I would definitely add material, as much as reasonable to make a bowl shape with a padded bottom layer. I personally would also try adding straw around her in a circle; she will likely rearrange it all herself but it seems like she needs a little assist in creating that bowl and borders so eggs...
Pictures of the nestbox?
There's a good article on how to create more natural nesting condition which includes the hen being able to make a nice "bowl" to keep eggs from rolling away or getting malpositioned by mistake. I'll see if I can find it...
Article...