An article with in-depth analysis of Nutella ingredients is Nutella: the full (correct) list of ingredients. An image from this article:
Another article with in-depth analysis of Nutella ingredients: Behind the Label: Nutella.
The art and science of reading food labels is explained in articles and videos below:
Articles by Jeff Novick: How To Read A Food Label: Part 1 and Part 2.
Videos by Jeff Novick:
DVD by Jeff Novick: Should I Eat That: How to Choose the Healthiest (DVD, 2010).
Videos by Dr Greger:
The Five to One Fiber Rule by Dr Greger (4 mins, YouTube).