Heat a large Dutch oven over medium heat. Cook the bacon until crispy, about 4–6 minutes. Transfer to a paper towel-lined plate. Pour off fat until about 1 tablespoon remains in the pot.
When cool enough, chop the bacon into small pieces and set aside.
Raise the heat to medium-high, add the chicken pieces to the bacon fat in a single layer. Sear for about 3–4 minutes, stirring occasionally until the edges turn golden.
Sprinkle the ranch seasoning over the chicken and stir to coat evenly.
Pour in the uncooked penne and chicken broth. Stir, bring to a boil, then reduce to a gentle simmer. Cover and cook for 15–20 minutes, stirring occasionally to prevent sticking.
Test a pasta piece for al dente doneness; there should be a little liquid left. Add a splash more broth if it looks too dry.
Cooking
Reduce heat to low, add cream cheese in dollops and stir until fully melted and the sauce is smooth.
Stir in the chopped bacon and 1.5 cups shredded cheddar. Mix gently until the cheese melts and coats the pasta.
Sprinkle the remaining 0.5 cup cheddar over the top. Cover the pot for 30 seconds to let residual heat melt it. For a browned top, transfer the Dutch oven under the broiler for 3–5 minutes, watching closely.
Serving
Sprinkle with chopped parsley and serve immediately.
Notes
Can swap penne for rigatoni or rotini; for gluten-free use GF penne and check ranch seasoning label. Freshly shred cheddar for the best melt. Store leftovers in an airtight container for up to 3–4 days, or freeze for up to 2 months.