In a large bowl, mix nutella with the crumbled cookies. Stir in milk by the tablespoon until you get a spreadable consistency. Spread this nutella mixture onto the brownie layer.
Freeze for 15 minutes while ice cream is softening on the counter.
Spread a layer of ice cream onto the nutella layer. If the ice cream is too soft to float snickers chunks, then freeze for 5-10 minutes until its sturdy enough.
Add the snickers, and drizzle the dulce de leche. Freeze for at least a 3-4 hours before serving.
To serve, let it sit on the counter for about 10 minutes to soften.
