Sauté carrots, onion and celery in olive oil over medium high heat. After 1-2 minutes add in garlic and salt and pepper. Sauté 2-3 minutes more until onions start to turn translucent and the veggies are tender.
Add chicken broth and bring to a boil.
Add tomatoes, Rotel, taco, taco seasoning, chicken and tortillas. Stir to combine.
Boil for 20 minutes or until the tortillas are thoroughly incorporated into the soup, stirring occasionally.
Reduce heat and stir in the shredded cheese. Simmer for 10 minutes.
Stir in the milk and simmer for an additional 10 minutes.
Check the consistency of the soup and add in more tortillas if you want a thicker consistency. Just simmer until the tortillas melt in.
Serve in bowls and top with your favorite garnishes.