Heat oven to 350°F. Line 13 x 9 x 2-inch baking pan with aluminum foil, letting foil overhang edges; generously coat foil with nonstick cooking spray.
In medium-size bowl, stir together the flour, baking powder and salt until well blended.
In medium-size saucepan, melt together the butter and peanut butter over medium-high heat. Remove the saucepan from the heat. Stir in the brown sugar and granulated sugar until well blended. Let the mixture cool slightly. Stir in the eggs and vanilla. Then stir in the flour mixture, white and milk chocolate chips, coconut and peanuts just until incorporated (mixture will be stiff and crumbly). Press batter evenly with rubber spatula into the bottom of the prepared pan.
Bake in 350°F oven until bar begins to pull away from sides of pan, 30 minutes. Transfer pan to wire rack; let cool completely. Use foil to lift bar from pan.
In small glass dish, melt together chocolate chips and oil in microwave oven on high power, about 1 minute. Stir until smooth. Scrape the chocolate mixture into a small plastic bag; snip off a small corner. Quickly drizzle the melted chocolate over the bar. Let cool until the drizzle is set. Cut into twenty-four 2-inch bars.