Cook the jumbo pasta shells according to package instructions until al dente. Drain and set aside to cool.
In a large bowl, combine the shredded chicken, chopped broccoli, ricotta cheese, half of the mozzarella, Parmesan cheese, garlic powder, onion powder, salt, and pepper. Mix until well combined.
Spread half of the marinara sauce evenly across the bottom of a 9x13 inch baking dish.
Carefully fill each cooked pasta shell with the chicken and broccoli mixture and arrange them in the baking dish.
Once all shells are filled, pour the remaining marinara sauce over the stuffed shells.
Sprinkle the rest of the mozzarella cheese on top of the stuffed shells.
Cover the baking dish with aluminum foil and bake for 25 minutes.
Remove the foil and bake for an additional 10 minutes, or until the cheese is bubbly and golden.
Garnish with fresh chopped parsley before serving.
Notes
Feel free to add more vegetables or spices to the filling as desired.