Looks nice, make sure you get some ventilation in the coop though. Ammonia build up from the chicken poop without proper ventilation will kill the birds. And if it gets below freezing in the winter, the humidity build up will cause frostbite and maybe respiratory problems.
You will want to put an angled roof over the nest box. What you have there is a big pile of chicken poop just waiting to happen. Given you have the coop on one side and a wall on the other, you can just make the top wider and hinge it up the wall maybe a foot. Might want to split the top in half or rig up some lifting hardware , that OSB gets heavy

Bruce