Preheat oven to 350°F. Lightly coat a 13- x 9-inch baking dish with cooking spray.

Microwave cream cheese and sour cream in a large microwave-safe bowl on HIGH until cream cheese is softened, about 1 minute and 30 seconds. Whisk together until smooth.

Stir in beans, green chiles, taco seasoning, salt, smoked paprika, chili powder, onion powder, cayenne pepper, and 2 cups of the cheese until well combined.

Transfer to prepared baking dish, and spread in an even layer. Top with remaining 2 cups cheese.

Bake in preheated oven until cheese is melted, about 25 minutes. Remove from oven, and top evenly with scallions. Serve with tortilla chips.