But this gonna lead to other problems. If a given product have multiple SKU and they are indexed as multiple documents, when a query is executed, the same item could return multiple times, but, in fact, its just a single product that must return, the sku separation is just a abstraction.
What i'm trying to say is, in the application, only the base product should be displayed, if the user click that product, inside the product page it show the skus, like in almost all ecommerces.
This thing i'm trying to do is to solve a problem when users ask for 'black dress' and the image displayed is a 'white dress', but there is a inner sku of that product that is white. With this the app can show the correct sku without the user need to enter the product to see if has the property it's searching.
Another thing that multiple sku documents generate is the incorrectness of count, aggregations, etc...
I'm not familiar with nested objects, but don't seems that if gonna help to identify whatis the sku the query hited, it may help in accuracy.