Assuming the Skeletons make it into combat with ~30 models remaining, and the Vampires enter combat largely unharmed, the Legion of Blood +1 attack buff provide a similar damage boost (mainly from the VLoZD) compared to Lord of Nagashizzar and doesn't require a linchpin hero, which seems helpful. However, there are no good Command Traits for a Necromancer general, and the re-rolling save rolls of 1 artefact isn't as good as Wristbands of Black Gold for the VLoZD, so I feel like I'd only be taking Legion of Blood for the Vampire attack boost (which is very fluffy but maybe not ideal).
Instead, Sacrament would buff army speed, casting, and VLoZD. Grand Host would buff Skeleton Warrior attacks and Skeleton Warrior durability. Tough choice.