To make this butter chicken, start by seasoning the chicken. In a large bowl, add the bite-sized chicken thigh pieces and sprinkle in the nutmeg, turmeric, cumin, chili powder, garam masala, and salt. Toss well to coat every piece evenly.
Next, heat a large skillet over medium heat and add the butter. Once the butter has melted and begins to bubble slightly, add the chicken in a single layer. Let it cook undisturbed for about 4 minutes, then flip and cook another 4 minutes on the other side until almost cooked through.
Add the mashed garlic, tomato paste, ketchup (if using), and the coconut milk. Stir well so the chicken is coated in the sauce.
Lower the heat to medium-low and let everything simmer gently for about 5 minutes. Remove from the heat and set aside.
While the chicken simmers, make the garlic naan. Preheat the oven to 375F and line up the naan on a baking sheet.
Brush with olive oil and mashed garlic and a pinch of salt.
Bake for six minutes.
Serve the butter chicken over rice with the warm garlic naan on the side. Sprinkle with the chopped parsley. Enjoy!