If you exercised and held NQSOs in 2018, and did not sell them in 2018, then there is nothing to report, other than the income that is already included in box 1 of your W-2. If you sold in 2019, you will report the sale then. Your cost basis will be the amount you paid plus any compensation added to your W-2 in 2018 due to the difference between the option strike price and the share price at the time of exercise.
