In a large bowl, combine the oats, brown sugar, butter, 1/2 cup peanut butter, corn syrup and vanilla. Press into a greased 13x9-in. baking pan. Bake at 375° for 12-14 minutes or until mixture is bubbly around the edges.
In a microwave-safe bowl, melt butterscotch and chocolate chips; stir until smooth. Stir in peanuts and remaining peanut butter; spread over the oat mixture. Cool for 10 minutes; chill until set.