Ingredient:

• 1 1/2 pounds skinless, boneless chicken breast, cut into 1 1/2-inch pieces
• 3/4 cup buttermilk
• 1/4 cup plus 2 tablespoons Sriracha, divided
• 1 red bell pepper, cut into 2-inch pieces
• 1 green bell pepper, cut into 2-inch pieces
• 1 onion, cut into 2-inch wedges
• 8 mushrooms, stems removed
• 1/3 cup sweet Thai chili sauce
• 2 tablespoons soy sauce
• 1/2 cup mayonnaise
• 1/2 teaspoon onion powder
• 1/2 teaspoon garlic powder
• 2 tablespoons vegetable oil, for oiling grill grates
• 2 green onions, thinly sliced
• 1 lime, cut into wedges (optional)