In a bowl, combine Greek yogurt, mayonnaise, sweet chili sauce, sriracha, lime juice, garlic powder, onion powder, salt, and black pepper. Mix until smooth.
Add the chicken cubes to the marinade, ensuring they are well coated. Cover and refrigerate for at least 30 minutes, or up to 2 hours for more flavor.
Preheat your grill or grill pan over medium-high heat. Thread the marinated chicken onto the skewers.
Grill the skewers for 10-12 minutes, turning occasionally, until the chicken is cooked through and has nice grill marks. The internal temperature should reach 165°F.
Remove from the grill and let rest for a few minutes before serving. Drizzle with extra sweet chili sauce if desired.