Bring a large pot of salted water to a boil. Add the pasta and cook according to package directions until al dente. Drain the pasta and set aside.

While the pasta is cooking, cook the bacon in a large skillet over medium heat until crispy. Remove the bacon from the skillet and drain on paper towels. Crumble the bacon and set aside.

In the same skillet, add the olive oil. Add the chopped onion and cook until softened, about 5 minutes. Add the minced garlic and cook for another minute until fragrant. Add the chicken and cook until cooked through, about 7-10 minutes. Season with salt and pepper to taste. The chicken should be lightly browned and cooked to an internal temperature of 165°F (74°C).

Reduce the heat to low. Add the softened cream cheese and milk to the skillet. Stir until the cream cheese is melted and the sauce is smooth and creamy. This may take a few minutes, so be patient and keep stirring.

Add the cooked pasta and crumbled bacon to the skillet with the sauce and chicken. Stir to combine until everything is evenly coated.

Stir in the ranch dressing.

Serve immediately, garnished with shredded cheddar cheese, chopped green onions, diced tomatoes, or chopped parsley, if desired.