Preheat oven to 350°F (175°C).

Grease and flour a 13 x 9 x 2-inch baking pan.

In a large bowl, stir together the flour, sugar, cocoa, baking soda, and salt.

Add the water, vegetable oil, eggs, vinegar, and vanilla to the dry ingredients.

Beat on medium speed for 2 minutes, until well combined.

Stir in the chocolate chips.

Pour the batter into the prepared pan.

Spoon heaping teaspoonfuls of Cream Cheese Filling over the batter.

Sprinkle with nuts, if desired.

Bake for 50 to 55 minutes, or until a wooden skewer inserted into the center comes out clean.

Let the cake cool in the pan before slicing and serving.