Line 2 baking sheets with parchment paper and set aside.
In a medium saucepan, cook the sugar, butter, milk and cocoa powder over medium heat until the butter has melted. Mix well. Bring to a rolling boil, then allow to boil for around 4 minutes.
Remove from heat, then mix in the Nutella and vanilla until smooth. Fold in the oats and dried cranberries.
Using a medium cookie scoop, scoop the cookie dough onto the prepared baking sheets. Allow to cool at room temperature, then store in an airtight container.