Spread a generous handful of mini-marshmallows onto a piece of foil that has been sprayed with non-stick spray. Toast under the broiler until lightly brown. Remove from heat.
In a blender, add three scoops of chocolate ice-cream, 3/4 c of milk, and a large gob (maybe 5 Tbs) of nutella. Blend until smooth.
Pour the shake into a tall glass. Top with marshmallows.