Nah nightfalls are easy even with the uber mods now, you don't need an elemental primary to complete them, at all. They're totally doable with elemental special and heavies with a good primary like a good pulse rifle or one of the billion year 2 Hawkmoons the game keeps shitting out of every exotic primary engram. The nightfalls LOOK bad when you're just reading the mods in orbit but once you get in they're a LOT easier than they sound.