Preheat oven to 350 F and grease a 9 x 13 baking pan.
Mix the brown sugar, ¾ cup margarine, eggs and vanilla together, then stir in the bisquick and oats until it reaches a uniform consistency.
Melt the chocolate chips in the microwave, then stir in the condensed milk, margarine, salt, nuts and 2 teaspoon vanilla extract.
Press about ⅔ of the oat mixture into the bottom of the prepared baking dish, then spread over the chocolate layer. Drop in the rest of the oat mixture and bake for 30 minutes or until lightly brown.