How do I fix double taxation from a NSQO sale that was also reported on my W-2?

It is possible that your cost basis on the sale reporte don your 1099-B needs adjusted.  I recommend removing the downloaded/imported E-trade info and entering the data yourself from a PDF or the printed version of the form to endure it's handled properly. 

TurboTax will ask you if this is employer stock and then will walk you through the steps.  The income reported on your W-2 becomes part of your basis, reducing any gain (and sometimes generating a loss) on the stock as reported on the 1099-B, but there are some limitations to the way that data is imported on 1099-B so this doesn't always get automatically captured.