Combine the milk and powdered sugar together in a saucepan and heat to a boil. Boil for one minute, stirring constantly to keep from burning. Remove from heat and set aside.
In a separate bowl, mix the marshmallow cream with the chocolate chips.
Pour the warm milk into the marshmallows/chocolate chip bowl. Stir until well mixed and smooth.
Pour into a buttered 8x8 pan. Let completely cool before cutting into small squares.