There is no shortage of shelving units suitable for a nursery these days, but we never tire of yet another option. We really like these Ply Grid Shelves by Offi. They are versatile and come in a nice Baltic birch finish that we love.
We also like the fact that they are hardware-free (read: no tools required for assembly!) They can be stacked horizontally (as shown) or vertically. It's great for toy and book storage, either alone or with bins and baskets tucked in the cubbies. Get it here and elsewhere.