Not to sound cooky but going solo is easy enough, just take it a lil slower make sure all mobs are dead before moving on, use range when ever possible so you don't get swarmed, and by now you should know spawns n which mobs so you should be able to plan your moves ahead of time which also goes for bosses.
Soo'd it 3 times last time, tedious as hell
Solo'd through the tank this time before bringing other people in, still tedious but this time I actually got a Gjallarhorn, so for once the nightfall felt like it was actually worth the reward.
Run past enemies in beginning, use black hammer or icebreaker to snipe the 3 shield majors and adds, snipe the tank in 2 mins, run past all other enemies to spam Valus with rockets and sniper rounds. Sure it would be tedious but not impossible
I always start my nightfalls solo because i like the challenge. But sometimes if friends join me midway or need one more in their team then we'll go with a full fireteam. The only exception to this is the recent omnigul nightfall with no burns. I was too lazy to solo that.
Its actually easier.
I attempted nightfall with 2 other warlocks and they only dragged me down. They weren't even helping.
They only messed up the rotation of valus.