As noted in the article, Nutella is made with palm oil, whose farming often results in habitat loss for animals such the Bornean orangutan, which is critically endangered. Ferrero claims they have a chain for palm oil such that it doesn’t come from devastating monoculture plantations, but whether that’s enough or even if it’s true at all isn’t my call to make for you. I don’t personally take palm oil as part of my diet as I see it as something I can practicably cut out to reduce harm, but whether this is vegan or just plant-based is something you’ll have to decide.