Short answer: it depends on your Parva (vrat) rules and tips you follow.

• Nutella contains milk powder, so it is not suitable for Jains who avoid dairy during Parushan (or who follow strict dairy restrictions).
• Some practitioners do stricter vrat and avoid processed foods or packaged sweets during Parushan; others may allow dairy or processed items if they fit their personal guidelines.
• Because Parushan rules vary between communities (and Digambar vs. Shwetambar practices can differ), the safest approach is to check with your guru or the guidance your community follows.

If you want, I can help you compare common Parushan guidelines from Jain traditions and suggest dairy-free, vratik alternatives.