Preheat the oven to 375°F (190°C). Set a 9-inch (23 cm) round, approximately 2-quart (1.9 L) oven-safe baking dish on a stable work surface. Make sure the dish is clean and dry so the filling can spread evenly.

In a large mixing bowl, combine: 8 ounces (225 g) softened cream cheese 1/2 cup (120 ml) Buffalo wing sauce 1/2 cup (120 ml) ranch dressing Stir firmly until the mixture becomes thick, smooth, and evenly orange, with no large lumps of cream cheese remaining. If the cream cheese is difficult to incorporate, continue working it against the side of the bowl with the spatula until it softens.

Fold in the 2 cups (280 g) cooked shredded chicken, 1/2 teaspoon (1.5 g) garlic powder, and 1/2 teaspoon (1 g) onion powder. Add 1/2 cup (about 57 g) mozzarella and 1/2 cup (about 57 g) cheddar. Stir until the chicken is evenly coated and the cheese is distributed throughout. The mixture should be thick enough to mound on a spoon rather than pour.

Transfer the mixture to the prepared baking dish and spread it into an even layer, smoothing the top with the spatula. Sprinkle the remaining 1/2 cup (about 57 g) mozzarella over the surface, followed by the remaining 1 cup (about 113 g) cheddar. Spread the cheddar evenly to create a continuous orange layer for the jack-o'-lantern face.

Place the baking dish on the middle oven rack and bake at 375°F (190°C) for 20 minutes, or until the cheese is fully melted, the edges are bubbling, and the center reaches 165°F (74°C). The top should be glossy and orange with a few lightly golden patches. If the center has not reached the required temperature, continue baking until it does.

Remove the dish from the oven and let the dip rest for 5 minutes. The cheese should remain soft but no longer move freely across the surface. Arrange the 1/4 cup (35 g) drained black olives into two triangular eyes, a small triangular nose, and a wide zigzag smile. Overlap the olive slices to make the shapes more visible. If using, sprinkle the 1 tablespoon (3 g) chopped fresh chives along the upper edge of the dip to add a small green decorative accent.

Place the baking dish on a heat-resistant trivet: Serve with the optional 10 ounces (about 285 g) sturdy tortilla chips arranged around the dish or in a separate serving bowl. The finished dip should be creamy beneath the melted cheese, with tender chicken throughout and enough structure to cling to a tortilla chip.