So I'm going to replay New Vegas again. But I'm looking for mods like the Dead Money Horror overhaul. In the sense of both overhauls and horror mods, perhaps both. Any recommendations and help is appreciated.

Unfortunately, if you're looking for horror type mods, there's not too many out there. While it makes New Vegas not very vanilla at all, something to consider is Obscurum Pandemic. That's a very hefty overhaul that makes the game pretty creepy and deadly.

This isn't lore friendly in any possible way alright? You could try Nevada Skies and set the mood to the Silent Hill variant. After that, mute the background music so that the only thing you'll hear are footsteps. Then add A World of Pain and Welcome to Hell and then use Harold's Wasteland mod to put a lush forest all over the Mojave.

Well... there are great npc overhauls by dragbody as @MotionlessGhost said perfectly but i must say there are not many horror mods out there i would just add the monster mod to your load order as it adds a bunch of well monsters into your game.