Preheat oven to 350 degrees. In large saucepan, over low heat, melt 1 cup chips with oleo. Beat in bisquick mix, sweetened condensed milk, 1 egg and 1 teaspoon vanilla. Stir in nuts and remaining one cup chips. Reserving 1 1/4 cup batter, spread remainder in well-greased 13x9 inch pan. In small mixer bowl, beat cheese, sugar, remaining egg and 1/2 teaspoon vanilla until smooth. Spread over chocolate batter. Place small spoonfuls of reserved chocolate batter over cheese mixture. With table knife or metal spatula, gently swirl through batters to marble. Bake 30 minutes or until brownies begin to pull away from sides of pan. Cool. Cut into bars. Store covered in refrigerator.