In a Crock Pot, stir together crushed tomatoes, chicken broth, oregano, basil, thyme, and garlic powder. Add in the chicken breasts, ensuring that the chicken is covered in the liquid.
Cook on low for 4-6 hours until the chicken is tender. Shred chicken with two forks.
Boil a large pot of water for the pasta then salt the water, add your pasta, and cook the pasta according to the package directions, about 10 minutes.
While the pasta is cooking, add the Greek yogurt, Parmesan cheese, and spinach to the Crock Pot. Cook on low for about 10 minutes.
Add the drained pasta to the Crock Pot and stir well. Serve immediately topped with additional Parmesan cheese, if desired.