Place chicken in a large pot and cover with cold water. Add rosemary, bay leaves, onion powder, garlic powder, lemon pepper, thyme, oregano, salt and pepper. Bring to a boil, reduce heat and simmer until chicken is done and tender. Remove chicken and set aside to cool then, de-bone and shred or chop the meat.
Preheat oven to 350 degrees. In a large mixing bowl, combine soup, sour cream, 3/4 pkg shredded cheese (reserve some for top), and butter. Mix well and stir in the chicken meat. Spread mixture evenly into a greased casserole dish. Top with remaining cheese and french fried onions. Bake for 15-25 minutes until hot and bubbly. Serve and enjoy!