Bring a large pot of salted water to a boil. Add the pasta and cook it until it is al dente, about 10 minutes. Drain and set it aside.
Add the bacon to a heavy-bottomed stock pot set over medium-low heat. Cook the bacon, stirring, until all the fat has rendered. Using a slotted spoon, transfer the bacon pieces to a bowl and set them aside. Leave all drippings in the pot. (If less than 2 tablespoons are in the pot, supplement with butter or olive oil.)
Add the chicken breasts and cook on one side for 4 minutes then flip once and cook until cooked through, about 4 more minutes. Remove the chicken to a plate and leave 2 tablespoons drippings in the pot. (If needed, supplement with butter, oil or bacon fat.)
Increase the heat to medium. Add the spinach. Cook, stirring, until wilted, about 2 minutes. Add the garlic and cook, stirring, for 1 minute. Sprinkle in the flour and cook, stirring, for 1 minute.
Add the heavy cream and sour cream and cook, stirring occasionally, until thickened slightly, about 5 minutes.
Stir in the Parmesan cheese, then stir in the pasta.
Dice the chicken then add it to the pot, along with the sun-dried tomatoes and reserved bacon. Stir to combine then serve.