In a spacious mixing bowl, combine the shredded chicken, basil pesto, halved cherry tomatoes, finely chopped red onion, and diced mozzarella cheese. Gently mix these ingredients with a spatula or large spoon until they are thoroughly combined.
Drizzle fresh lemon juice over the mixture. Season with salt and pepper to taste. Stir gently yet thoroughly to ensure that all ingredients are evenly coated in the pesto.
Select a fresh lettuce leaf and place a generous spoonful of the pesto chicken salad mixture in the center of the leaf.
Carefully fold the sides of the lettuce leaf over the filling to create a delightful cup shape. Continue this process with the remaining lettuce leaves and filling until all components are used.
For an added touch of flavor and visual appeal, optionally garnish each lettuce cup with fresh basil leaves.
Notes
Arrange the finished lettuce cups on a colorful platter for a vibrant display. Consider drizzling additional pesto around the platter for extra decoration and a burst of flavor.