In a large pot, bring salted water to a boil. Cook the jumbo pasta shells according to package instructions until al dente. Drain and set aside on a baking sheet to prevent sticking.
In a mixing bowl, combine shredded chicken, basil pesto, ricotta cheese, minced garlic, half of the mozzarella cheese, and Parmesan cheese. Season with salt and pepper to taste. Mix until fully combined.
Take each jumbo shell and carefully fill it with the chicken and cheese mixture using a spoon or piping bag.
Spread a thin layer of pesto on the bottom of a baking dish. Place the stuffed shells in the dish, open side up.
Drizzle the remaining pesto over the stuffed shells, then sprinkle the rest of the mozzarella cheese on top.
Cover the dish with aluminum foil and bake for 20 minutes in the preheated oven. Remove the foil and bake for an additional 10 minutes or until the cheese is bubbly and golden.
Remove from the oven and let it cool for a few minutes. Garnish with fresh basil leaves before serving.
Notes
Feel free to add more vegetables to the filling for extra nutrition.