As a fan of Nekusar, the Mindrazer, I can confidantly say that this deck looks really solid. Something I've always liked is Library of Leng. It lets you discard cards you may want to keep back to the top of your deck, which allows you to keep your best stuff when you wheel everyone elses best toys away. Sangromancer can offer a bit of extra life in case you end up being a a target. Reinterpret is a wild counterspell that can lead to some fun plays and drop bombs while also interrupting your opponents plans. Feed the Swarm gives you another way to potentially deal with pesky enchantments. Burning Inquiry is just a pet card of mine. Can really mess up peoples plans. Wheel of Misfortune needs to be read and re-read 7 times, but it puts in so much work while being just a touch chaotic. Wheel and Deal can also really mess with people, especially since its a wheel at instant speed. You are already running Notion Thief, so Narset, Parter of Veils is just another way to lock out extra card draw. Bloodchief Ascension gets out of hand really fast, and very quickly ends the game. last thing, Tinybones, Trinket Thief is a nice little card draw engine that doubles as a wincon. If you are having a hard time trying to find cuts, I have noticed there are quite a few cards in the deck that have really high mana values. I would personally start there. I am not sure your budget, so feel free to take all of these suggestions as you see fit. From one Grixis player to another, I wish you the best of luck with your deck.

Ajuntoson, thanks for the suggestions! Added some of these to the maybeboard. Bloodchief Ascension for sure. Am currently building a couple of more decks since i've been struck by the bug, but will absolutely take a look at these. Thanks!