Login to your Nice Hash account.
Navigate to the Wallets page.
Nice Hash only allows export per wallet, therefore in order to get all the historical data it is necessary to navigate to every wallet used and export files one by one.
e.g. Navigate to your ETH wallet and press the Export button.
Set the timezone to GMT and click the Create button.
You will receive a notification via email when your report is generated. Open the email and press the Open Report button, a new tab will open with the list of your Reports.
Press the action Download report
Navigate to the Nice Hash tab on CryptoTrader.Tax and drag each of your CSV files into the blue box to import your transactions.