Adjust an oven rack to the lower-middle position and preheat to 350 degrees F. Spray a 9x13-inch baking pan with non-stick spray. Line the pan with two overlapping pieces of foil or parchment paper, leaving the overhang to act as handles for lifting the bars out of the pan. Spray with non-stick spray.
Combine the melted butter and graham cracker crumbs in a small bowl. Toss with your fingers until the butter is evenly distributed. Spread the crumbs evenly over the bottom of the prepared pan (this is not meant to be a crust, so you don't need to press it flat and there will be some small bare spots along the bottom, that's okay).
In this order, sprinkle the pecans, chocolate chips, white chocolate chips, butterscotch chips, and coconut over the graham crumbs. Pour the condensed milk evenly over the entire dish.
Bake until the top is golden brown, about 25 minutes. Cool in the pan on a wire rack to room temperature, about 2 hours.
Remove the bars from the pan using the foil or parchment handles and transfer to a cutting board. Using a sharp knife or bench cutter, cut into 2 by 3-inch bars.