Well this changes things. If it was just amending one return then it would be worth it. Thank you for pointing that out.

I had meant to say that the 2018 NOL carry back goes to 2013 and can be completely used in 2013. - So as you pointed out this one would require an amendment since the NOL is from 2018 and the time limit has passed to use 1045.

The 2020 NOL carry back would go back to 2015 and can be completely used in 2015. So the 1045 for 2015 is related to the 2020 NOL, not the 2018 NOL.

So to summarize, I would have to file an amended 2019 return, amended 2013 return, and then would I be able to file the 2015 1045 with the 2020 return since it is related to the 2020 NOL?

Am I understanding correctly? 

After all of this, I am not sure it is worth the difference in tax savings. At least I am learning 🙂

EDIT: I am reaching here but I am guessing it is not allowable for us to carry back the 2020 NOL to 2015 via form 1045 without also carrying back the 2018 NOL? I just want to make sure I have done everything I reasonably can do before saying its not worth the trouble.