In a large resealable plastic bag, marinate chicken with vinegar, olive oil, and garlic for at least 30 minutes. Saute in a little olive oil until done. Set aside.

Cook pasta in a large pot of boiling water until al dente. Drain, and set aside.

Meanwhile, melt butter or margarine in a small saucepan over medium-high heat. Add heavy cream, salt, nutmeg, and ground black pepper, and stir until sauce thickens. Reduce heat to low. Add grated Parmesan cheese, and stir until the cheese melts. Set Alfredo sauce aside.

In a large bowl, mix together ricotta cheese, egg, oregano, marjoram, and basil. Mix in cooked chicken.

Stuff cooked manicotti shells with chicken and ricotta mixture. Cover the bottom of a 9x13 inch baking dish with half of the Alfredo sauce. Place stuffed shells on top of sauce. Pour remaining sauce over shells. Top with one cup shredded mozzarella cheese. Cover with aluminum foil.

Bake at 350 degree F (175 degree C) oven for 45 minutes. Let stand 10 minutes before serving.