In a small bowl, whisk together the Greek yogurt, light mayonnaise, lime juice, chili powder, cumin, garlic powder, salt, and pepper until completely smooth.

In a large mixing bowl, combine the diced chicken, corn, finely diced red onion, crumbled cotija cheese, chopped cilantro, and minced jalapeño if using.

Pour the prepared dressing over the chicken and corn mixture. Gently fold everything together until every ingredient is well coated with dressing.

Taste and adjust seasoning with additional salt, pepper, or lime juice if needed. Cover and refrigerate for at least 30 minutes before serving.