Preheat the oven to 325 degrees F (165 degrees C). Lightly grease a large glass baking dish.

Mix graham cracker crumbs and butter together in a bowl until thoroughly moist. Transfer to the bottom of the prepared pan and press to flatten evenly. Pour condensed milk over top, leaving about a 1/4-inch border around the edges.

Mix walnuts, pecans, almonds, coconut, milk chocolate chips, white chocolate chips, butterscotch chips, raisins, chocolate syrup, and caramel topping together in a bowl. Pour on top of condensed milk all the way to the edge.

Bake in the preheated oven until a toothpick inserted into the center comes out mostly clean and edges are golden, 20 to 25 minutes. Remove from the oven and let cool completely before cutting into 1 1/2-inch squares to serve, about 30 minutes.