Black Metal.

I've never understood why Deathspell Omega were so good. I've tried to listen to it a lot but I am always bored by it. I think it's more me not getting it than them being a bad band though because of how many people with otherwise good taste are so into then.

I guess I'll keep trying then. It's hard to motivate myself to do that though when there is so much black metal and music in general that clicks with me right away.

I highly recommend their first two albums. More straightforward and Darkthrone-influenced.
 
But Nick might like them more, and they could get him into newer stuff by the band...for instance "Drink the Devil's Blood" on SMRC is a recontextualized version of a song by the same name off their debut LP.
 
Except those 2 albums, while good, are completely irrelevant to showing why they are unique as a band.

Yes, but for someone who's favorite type of Black Metal is simpler and melodic a la Darkthrone, their earlier stuff should be more appealing. The best way to understand DsO from that perspective is to start at the beginning.