Preheat oven to 350 degrees F.
In a large bowl, combine softened cream cheese, mayonnaise, and 1 cup of shredded mozzarella cheese. Mix with a hand mixer until smooth and creamy.
Chop imitation crab meat into ½- to 1-inch pieces and add to the bowl.
Stir in chopped green onions, tamari or soy sauce, sweet chili sauce and minced garlic.
Add garlic powder and onion powder, mixing until fully combined.
Transfer mixture to a 1- to 1 ½-quart baking dish and spread into an even layer.
Sprinkle remaining ¼ cup mozzarella cheese over the top.
Bake for 25 minutes, switching the oven to broil for the final 2 minutes to lightly brown the top.
Remove from oven and garnish with extra sweet chili sauce and additional green onions, if desired.