Heat oven to 350 degrees and grease a 9X13-inch pan.
Place all crust ingredients in a large bowl and use an electric mixer to mix them until crumbly.
Press half of crumb mixture into the bottom of prepared pan. Reserve remaining crumb mixture for topping.
To make filling, in a heavy-bottom saucepan, heat chocolate chips and cream over low heat, stirring constantly, until smooth.
Turn heat off and whisk in half the Nutella. Then add the second half and whisk it in.
Whisk in confectioners' sugar. Pour filling over bottom layer and smooth it into an even layer.
Sprinkle remaining crust mixture evenly on top.
Bake for 40 to 45 minutes. Lett cool before cutting into squares.