Preheat oven to 375°F with oven rack positioned in center. Lightly spray a 2-quart baking dish with cooking spray; set aside. Whisk together cream cheese, mayonnaise, scallions, soy sauce, Sriracha, garlic powder, onion powder, salt, white pepper, and 1 tablespoon of sweet chili sauce in a medium bowl until combined. Fold in crab and 2 cups of the cheddar until combined. Spoon into prepared baking dish, spread into an even layer, and sprinkle evenly with remaining 1 cup cheddar.

Bake until cheese has melted and mixture is bubbling and starting to brown around edges, 25 to 28 minutes. Without removing dish from oven, increase oven temperature to broil, and broil until cheese has started to brown on top, 3 to 4 minutes.

Meanwhile, pour oil to a depth of 2- to 3-inches in a heavy-bottomed pot or Dutch oven. Heat over medium-high until a candy or instant-read thermometer registers 350°F. Working with about one-third of the wontons at a time, carefully add wontons to oil and cook, turning often, until golden brown, crispy, and small bubbles have formed on wrappers, 30 seconds to 1 minute. Remove with a slotted spoon to a paper towel-lined baking sheet and season with salt to taste. Repeat with remaining wonton wrappers. Set wonton chips aside.

Remove dip from oven and let sit for 5 minutes. Drizzle with remaining 2 tablespoons sweet chili sauce. Garnish with dark greens of scallions and serve with fried wonton chips.