Cook bacon in a skillet over low to medium-low heat until crispy. Remove bacon and drain on paper towels; reserve a tablespoon of bacon fat in the pan.

Season chicken breasts with salt, pepper, onion powder, and Italian seasoning. Sear the chicken in the same skillet (with bacon fat) over medium-high heat until golden and cooked through, about 4–6 minutes per side depending on thickness. Remove and let rest before cubing.

Bring a pot of salted water to a boil. Boil the rotini according to package directions until al dente. Drain and set aside.

In the skillet, melt butter over medium heat. Add minced garlic and sauté until fragrant, about 30 seconds.

Sprinkle in the flour and whisk constantly for 1 minute to form a roux.

Gradually whisk in the half and half until smooth and slightly thickened. Stir in the ranch seasoning.

Reduce heat, then fold in shredded cheddar a handful at a time until the sauce is creamy and smooth. Season to taste with salt and pepper.

Add cubed chicken and cooked pasta to the sauce. Toss gently until everything is well-coated.

Plate and garnish with chopped crispy bacon before serving.