NOL carryover from 2017: Do I have to use it in my 2018 declaration even if I would owe no tax without it?

I have a NOL to carry over from 2017.  I relinquished any carryback.  Even without using the loss in my 2018 declaration, I have zero federal tax liability for the 2018 tax year.  Do I have to enter the loss on my 2018 declaration, or can I wait and use it later in a year when I may otherwise have to pay federal tax?