Bring a large pot of lightly salted water to a boil; cook rotini at a boil until tender yet firm to the bite, about 8 minutes. Drain rotini, saving 1/2 cup of pasta water.

Meanwhile, place bacon in a large skillet and cook over medium-high heat, turning occasionally, until evenly browned and crispy, about 10 minutes. Remove bacon and drain on paper towels. Leave rendered bacon grease in the skillet.

Sprinkle chicken pieces with 1 tablespoon ranch seasoning. Add to the skillet with the bacon grease and cook until golden brown, 5 to 8 minutes. Remove cooked chicken from skillet and set aside.

Rinse out skillet to make the sauce. Melt down 2 tablespoon butter in the skillet over medium heat. Whisk in flour until smooth and thickened, about 2 minutes. Slowly add in milk, whisking until sauce is smooth. Add pasta water, 1 tablespoon at a time, if the sauce is too thick.

Stir softened cream cheese into sauce until well combined. Mix in remaining 5 teaspoons of ranch seasoning and season with salt. Mix until well combined. Add cooked pasta and chicken back into the skillet and mix until well coated with sauce.

Finely chop cooked bacon. Mix into pasta dish. Serve garnished with chopped parsley if desired.