In a large pot over medium heat, melt butter. Cook onion and celery in butter until soft and slightly translucid, 5 minutes. Pour in chicken broth and stir in chicken, noodles, carrots, chives, oregano, salt, and pepper. Bring to a boil, then reduce heat and simmer 20 minutes. Serve and add a few drops of Molli Morelia taqueria hot sauce to add a smoky and slightly spicy touch to your soup. Provecho!