For the stock: Place the chicken in a pot and add the garlic, bay leaves, carrots, parsley, rosemary, thyme, peppercorns, lemon and onion. Cover with 12 cups water and bring to a boil. Reduce the heat and simmer at a low rolling boil for 40 minutes. Remove the chicken and let cool. Strain the stock, then return it to the pot and simmer until reduced to about 8 cups. Discard the skin and bones of the chicken and shred or dice the meat.
For the soup: Heat the EVOO in a soup pot over medium-high heat. Add the carrots and cook for a few minutes, then add the leeks and cook until softened, a few more minutes. Add the escarole and cook until wilted. Season with salt, pepper and a little nutmeg. Add the chicken and stock, and heat through.
Bring a large pot of water to a boil for the pasta, and season with salt. Add the pasta and cook until al dente.
Divide the pasta among 4 bowls, nesting a bundle of noodles in each dish. Ladle the soup over the pasta and serve.
The soup (without the pasta) can be made ahead of time, cooled and then stored in the refrigerator.