Cook pasta according to package directions and set aside.

Cook bacon in a large skillet until crisp, then drain on paper towels. Chop bacon when cool enough to handle. Drain most of the bacon drippings from the pan, leaving about 1 tbsp. Return pan to medium hit heat.

Season chicken with salt and pepper, add into the skillet with bacon drippings, and cook until no longer pink and becomes golden brown, about 4-6 minutes.

Add in milk and ranch dressing packet, and stir well. Cook until thick and bubbling. Add in cheddar cheese and 1/2 of the reserved bacon. Cook, stirring regularly until the cheese is melted. If the sauce becomes too thick, thin it out with some fat-free chicken broth as needed.

Spoon sauce over pasta, and serve with remaining bacon and green onions sprinkled on top.