The election to waive the NOL carryback period is on screen 41 in the form 1120 program for 2019. Note that there is a check box at the top of the screen and also a separate section for CARES ACT NOL Elections on the same page. It used to be located on screen 23.1 in years through 2017.

Refer to Rev. Proc 2020-24 for more info. on the Cares Act Elections. Here is some general info.

A taxpayer’s election to forego carrybacks for NOLs arising in a taxable year beginning in 2018 or 2019 must be made by the due date (including extensions of time) for filing the return for the taxpayer’s first taxable year ending after March 27, 2020.  Thus, a calendar year taxpayer must elect for either 2018 or 2019 NOLs by the extended due date for the 2020 return, which would be October 15, 2021. A taxpayer’s election to forego carrybacks for NOLs arising in a taxable year beginning in 2020 must be made by the due date (including extensions of time) for filing the return for that year.  It is expected that the Internal Revenue Service (IRS) will soon issue procedural guidance on how to either request refunds for NOL carrybacks or elect to forego carrybacks, similar to guidance issued for the 2009 five-year NOL carryback legislation (Rev. Proc. 2009-52).