Bring a large pot of water to a boil. Salt it with the kosher salt, and cut the chicken into bite-size chunks, bacon into 1-inch pieces, mince garlic, and grate Parmesan.

Add rotini and cook until al dente according to package directions. Reserve 1 cup pasta water, then drain.

Place bacon in a cold 12-inch skillet and set over medium heat. Cook 6 to 8 minutes, turning occasionally, until browned and crisp. Transfer to a plate, pour off excess drippings, and leave about 1 tablespoon in the skillet.

Add chicken to the skillet and cook 2 to 3 minutes, turning, until heated through with lightly browned edges. Transfer it to the plate with the bacon.

Reduce heat to medium-low. Add butter and garlic; cook 30 seconds. Whisk in cream, broth, ranch seasoning, and cream cheese. Simmer 3 to 4 minutes, stirring, until smooth and slightly thickened.

Remove skillet from heat and whisk in Parmesan a handful at a time. If sauce is tight, whisk in 1 to 2 tablespoons reserved pasta water.

Add rotini, chicken, bacon, black pepper, and parsley. Toss until glossy, adding more pasta water a tablespoon at a time if needed, and serve hot.