The somewhat aged body of the subject, coupled with the flavor of the card, also recalls our fears of aging, of dementia, and of being alone, and misunderstood
Take Esper self-bounce in Standard, for example
Getting a free spell at some point is pretty sweet, but this feels more like a legends-matter support piece than a generally playable card
Dracula Series The Dracula series cards bring Bram Stoker's Dracula novel to life within Magic
Its not like you want to use your Murder on a one-drop anyway
Even if you weren't immediately boosted in this way, Nissa would still be pretty tricky to deal with, as she turns your lands into vigilant creatures that can attack and then block, right away