Preheat your oven to 400°F.
Season the chicken breast with a pinch of salt, pepper, and dried thyme. In a small skillet, heat olive oil over medium heat and sear the chicken for 3-4 minutes on each side until lightly golden; it does not need to be fully cooked at this point.
In a food processor, blend the cauliflower until it reaches a rice-like consistency. Transfer to a bowl and mix in the egg and Greek yogurt. Season lightly with salt and pepper.
Chop the onion, carrot, and prepare the green peas. In the skillet used for the chicken (add a splash of olive oil if needed), sauté the onions until translucent, then add the carrots and peas. Cook for about 3-4 minutes.
Deglaze the pan with low-sodium chicken broth, scraping any bits off the bottom. Simmer for another 2 minutes.
In a baking dish, place the seared chicken breast and spoon the sautéed vegetables over it. Carefully spread the cauliflower mixture over the top, ensuring it covers the filling evenly.
Bake in the preheated oven for 18-22 minutes, or until the chicken is fully cooked and the cauliflower crust sets with a light golden color.
Remove from the oven, let it rest for a few minutes, then serve warm and enjoy your hearty, creamy pot pie.