Heat olive oil in a large skillet over medium heat. Add diced potatoes in a single layer and cook for 8-10 minutes, stirring occasionally, until golden brown and fork-tender.

Season chicken breasts generously with salt, pepper, and garlic powder on both sides. Remove potatoes from skillet and set aside. Cook chicken breasts for 5-6 minutes per side until internal temperature reaches 165°F.

Remove chicken from skillet and let rest for 5 minutes before slicing. Add minced garlic to the same skillet and cook for 1 minute until fragrant.

Pour in heavy cream and chicken broth, whisking to combine. Bring to a gentle simmer and cook for 3-5 minutes until sauce thickens enough to coat the back of a spoon.

Reduce heat to low and gradually stir in mozzarella and Parmesan cheese until melted and smooth. Add fresh thyme and season with salt and pepper to taste.

Return potatoes to the skillet and fold into the creamy sauce. Slice chicken into strips and arrange on top. Simmer together for 2-3 minutes, then garnish with fresh parsley before serving.