In a large pot, sauté the shallots with butter for a few minutes. Then add the tomato and jalapeno and cook another 2 minutes. Add the stock, and lime zest/juice, cover and let simmer for 20 minutes.
Add shredded chicken and season with salt and pepper.
To serve, pour soup into bowls then add some cilantro, avocado and broken corn chips to each bowl. Top with sour cream if you like.
Notes
*For an even quicker meal, use pre-cooked BBQ chickens from the grocery store