In a large bowl, cream together butter and sugar. Stir in eggs and vanilla extract. Stir in flour, baking soda, salt and oatmeal. Spread ⅔ of batter in a greased 9×13 pan.
To make filling, melt chocolate chips, sweetened condensed milk, salt and butter in a small saucepan over medium low heat. Stir in vanilla extract and pecans. Pour over batter in pan. Top with spoonfuls of remaining dough.