As of 2017, with 2018 Tax Cuts and Jobs Act (TCJA), you can no longer carry back an NOL.
Most taxpayers no longer have the option to carryback a net operating loss (NOL). For most taxpayers, NOLs arising in tax years ending after 2017 can only be carried forward. The 2-year carryback rule in effect before 2018, generally, does not apply to NOLs arising in tax years ending after December 31, 2017. Exceptions apply to certain farming losses and NOLs of insurance companies other than a life insurance company. Also, for losses arising in taxable years beginning after Dec. 31, 2017, the net operating loss deduction is limited to 80% of taxable income (determined without regard to the deduction).