Grease bottom only of square baking dish, 8x8 x 2 inches.
Mix brown sugar, margarine, egg and vanilla.
Stir in flour, oats, baking powder and salt.
Spread evenly in baking dish.
Sprinkle with chocolate chips and nuts.
Microwave uncovered 4 minutes; turn dish one quarter turn.
Microwave until no longer doughy, 2 to 3 minutes.
Cool; cut into about 2 inch squares.