Heat olive oil in a skillet over medium heat. Season chicken with garlic powder, salt, and pepper.
Cook chicken for 6-7 minutes per side, or until fully cooked. Let rest for 5 minutes, then dice into small pieces.
In a bowl, mix the pesto, Greek yogurt, and lemon juice until smooth.
Add diced chicken, cherry tomatoes, red onion, and Parmesan cheese to the pesto mixture. Stir until well coated.
Lay out the lettuce leaves and spoon the pesto chicken mixture into each leaf.
Serve immediately or refrigerate for a cool, refreshing lunch or dinner.
