Pat chicken dry, brush with olive oil, season, and let sit at room temperature.
Preheat oven to 400°F (200°C). Toss bread cubes with olive oil, garlic powder, salt, and pepper. Bake 8-12 minutes until golden, then cool.
Mix mayonnaise, Greek yogurt, lemon juice, Dijon mustard, minced garlic, Parmesan, Worcestershire, and water until smooth. Adjust water for desired consistency.
Grill chicken 5-7 minutes per side until cooked through. Rest for 5 minutes, then slice thinly.
Massage half of the dressing into torn kale leaves for 1-2 minutes. Toss kale with most of the croutons and Parmesan. Add sliced chicken, remaining croutons, and Parmesan. Drizzle with remaining dressing before serving.
Notes
Ensure chicken is fully cooked and rest before slicing for maximum juiciness.