Make the Corn Salad: In a bowl, stir together corn, mayo (if using), lime juice, feta, and chili powder. Set aside.
Blend the Sauce: In a blender or food processor, combine avocado, Greek yogurt, lime juice, cilantro, garlic, and olive oil or water. Blend until smooth and creamy. Season with salt to taste.
Cook the Chicken: Toss chicken with olive oil, lime juice, and spices. Let it marinate for at least 15 minutes. Cook in a skillet over medium-high heat until browned and cooked through, about 8–10 minutes.
Assemble Your Bowls: Layer chicken and corn salad into bowls with or without rice. Add diced avocado, chopped cilantro, a drizzle of the sauce, and a sprinkle of extra feta. Serve with lime wedges on the side.