Add the milk and chicken broth. Bring to a gentle simmer and turn heat to low for 10 minutes.
Meanwhile, place the chicken thighs at the bottom of your slow cooker and add the seasonings. Top chicken thighs with sun-dried tomatoes.
When the cream sauce is ready (it should coat the spoon), lower the heat and whisk in parmesan cheese until smooth.
Pour the cream sauce evenly over the tops of the chicken thighs in the slow cooker.
Cook for 3-4 hours on high or 6-8 hours on low. Once ready, gently remove the chicken thighs.
Add spinach and stir until wilted.
Return the chicken to the slow cooker, and spoon the cream on top. Serve your chicken thighs over zucchini noodles, cauliflower rice or whole wheat pasta.