Heat a large skillet over medium high heat. Add olive oil and sear the chicken until golden brown and mostly cooked, about 3-5 minutes on each side.
Remove chicken and set aside. Add minced garlic, if using
Cook until fragrant, about 1 minute.
Add heavy cream, chicken broth, Italian seasoning, and grated parmesan cheese (if using garlic powder add at this point).
Whisk cream mixture over medium high heat until it starts to thicken, about 5-8 minutes.
Add the chopped spinach and sundried tomatoes.
Bring to a simmer and cook until the spinach starts to wilt.
Add the seared chicken back into the pan and toss to coat in the sauce.
Simmer chicken in sauce until fully cooked. Serve over pasta, if desired.