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 in a small saucepan over medium-high heat. Add 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 shredded cooked chicken.
Stuff cooked cannelloni shells with chicken and ricotta mixture. Cover the bottom of a 20x30cm baking dish with half of the alfredo sauce. Place stuffed shells on top of sauce. Pour remaining sauce over shells. Top with one cup grated mozzarella cheese. Cover with aluminium foil.
Bake at 180C oven for 45 minutes. Let stand 10 minutes before serving.