Prep the ingredients: chop the bacon, dice the onion, celery, and carrots, mince the garlic, and cut the chicken into bite-sized pieces. Soften the cream cheese at room temperature while you work.
Cook the bacon in a large Dutch oven or heavy pot over medium heat until crisp, about 6–8 minutes. Transfer to a paper towel-lined plate, reserving 1–2 tablespoons of the fat in the pot (add olive oil if there isn’t enough).
Season the chicken with a little salt and pepper, then increase the heat to medium-high and brown the pieces in the bacon fat until lightly seared on the outside, 3–4 minutes (they do not need to be cooked through). Remove the chicken to a plate.
Reduce heat to medium and add the onion, celery, carrots, and garlic to the pot. Sauté until the vegetables have softened and the onion is translucent, about 5–7 minutes, scraping up any browned bits from the bottom of the pan.
Stir in the cream of chicken soup, ranch seasoning, and chicken broth. Return the seared chicken to the pot, bring the mixture to a simmer, then cover and cook gently for 18–22 minutes, until the chicken is cooked through and the vegetables are tender.
Remove the chicken with a slotted spoon, shred it with two forks, and return it to the pot. In a small bowl, whisk the softened cream cheese with 1/2 cup of the hot broth until smooth, then stir that mixture into the soup to make it creamy. Add the shredded cheddar in batches, stirring until melted.
Add the frozen tortellini directly to the simmering soup and cook uncovered for 8–12 minutes, stirring occasionally, until the pasta is tender and floating. If the soup becomes too thick, thin with up to 1/2 cup additional broth or water.
Stir in most of the chopped bacon (reserve a little for garnish). Taste and adjust salt and pepper. Serve hot, finished with the remaining bacon and a sprinkle of parsley.