Place chicken thighs and buffalo sauce in pressure cooker. Cook on high for 20 minutes. Release pressure.
Preheat oven to 375°F.
Shred fontina and cheddar cheese. Mix together.
Transfer cooked chicken and sauce to mixing bowl. Shred chicken.
Stir in cream cheese and half the shredded cheese until smooth.
Spread mixture in a 10-inch cast iron skillet. Top with remaining cheeses and blue cheese crumbles.
Bake for 15–20 minutes until cheese is melted and bubbling.
Decorate with tortilla chips to form a jack-o’-lantern face just before serving.
