Darwin is very similar, one of his nests is beside his wheel! He does look adorable in the sand bath because it's right at the front of the cage and I can see his eyes closed
The bottom layer is quite dark because of the shelves, so I'm thinking he prefers an open nesting area at the bottom layer, I have a large tent like thing there that he never uses so I'm thinking of removing that so he has a bit more room on the bottom floor.