Begin by boiling a large pot of salted water. Once boiling, add the jumbo pasta shells and cook according to the package instructions until al dente. Drain and set aside to cool slightly.
In a skillet, heat 1 tablespoon of olive oil over medium heat. Add the cubed chicken breasts and cook until they are no longer pink, about 5-7 minutes. Stir in 1 tablespoon of Italian seasoning, and remove from heat.
In a mixing bowl, combine the cooked chicken, ricotta cheese, and half of the shredded Parmesan cheese. Mix well until all the ingredients are combined and season with salt and pepper to taste.
Preheat your oven to 375°F (190°C). Spread a layer of marinara sauce on the bottom of a baking dish. Stuff each cooked pasta shell with the chicken and cheese mixture, placing them seam-side up in the baking dish.
Once all the shells are stuffed, pour the remaining marinara sauce over the top. Sprinkle the remaining shredded Parmesan cheese evenly over the sauce.
Cover the baking dish with aluminum foil and bake for 25 minutes. Then, remove the foil and bake for an additional 10 minutes, or until the cheese is bubbly and golden.
