Bring a large pot of generously salted water to a boil. Cook pasta according to package directions. Reserve ½ cup of pasta water before draining pasta, then drizzle with the olive oil and toss to coat, to prevent sticking. Set aside.

In the same pot, cook the bacon over medium heat until crispy, about 6 minutes. Drain bacon on a paper towel-lined plate.

Reserve 3 tablespoon of the bacon grease in the pot. Over medium heat, add garlic and sauté for 20 seconds until fragrant. Add flour and stir 1-2 minutes until no white patches remain, reducing the heat if it begins to brown. Slowly whisk in the milk a little at a time to incorporate and then bring to a boil. Boil for 2-3 minutes until thick.

Remove pot from the heat. Whisk in Monterey Jack cheese, ranch seasoning, and the cream cheese until melted and smooth.

Add cooked pasta, shredded chicken, and most of the cooked bacon (reserving some for garnish), stir to incorporate. Place back on low heat for a couple minutes to re-warm pasta, adding a splash of the reserved pasta water to thin it out, if needed.

Taste for seasoning, adding salt and pepper if needed. Serve immediately with more cheese and crumbled bacon. The sauce will thicken pretty fast as it stands.