Stir together first 4 ingredients in a medium bowl until batter is smooth. Spoon half of brownie batter into a lightly greased 3-quart slow cooker.
Beat cream cheese and butter at medium speed of an electric beater until creamy; gradually add sugar, beating well. Add 2 eggs, 1 at a time, beating until blended. Stir in vanilla. Fold in flour and chocolate chips.
Pour cream cheese mixture over brownie batter in slow cooker. Dollop remaining brownie batter over cream cheese mixture; swirl mixture gently with a knife.
Cover and cook on LOW setting 5-1/2 hours or until set. Carefully remove slow cooker insert from heat element; let stand 45 minutes before serving