In a bowl, beat cream cheese and 1/3 cup sugar until light and fluffy. Beat in 1 egg; set aside.
In a saucepan, bring water, butter and chocolate to a boil, stirring occasionally. Remove from the heat. Stir in flour and remaining sugar. Stir in the sour cream, baking soda, salt and remaining eggs until smooth.
Pour into a greased 15x10x1-in. baking pan. Dollop cream cheese mixture over the top; cut through batter with a knife to swirl cream cheese mixture. Sprinkle with chocolate chips.
Bake at 375° for 30-35 minutes or until a toothpick comes out clean. Cool on a wire rack.