How can I bulk add entries in the blocklist?

I have been spending quality time with uBlacklist, and my list of removed domains has grown and I would like to now block them via NextDns as well. 

Presently I am cutting and pasting it line by line into the DenyList but it is going to take a lot of time. 
Being able to bulk add would be welcome.

Then I figured perhaps I can format it into a blocklist and import it that way, but 
I have not found the right buttons to configure a brand new (private to me) blocklist. 

What is the best solution?