In a large bowl, mix together the coconut milk, tomato passata, peanut butter, curry paste, minced garlic, and coconut sugar, until well combined and creamy. Set aside.
Heat coconut oil in a large pan or skillet over medium-high heat. Sear the chicken until browned on both sides (about 5 minutes each side). Lower the heat to medium, add the sauce, and bring to a boil. Cover and continue cooking for 15 minutes. Take the lid off, turn the heat to low, and allow the sauce to thicken (about 10 minutes). Once thick, stir in the lime juice and season with salt. Take off the heat and garnish generously with fresh mint leaves, peanuts, lime wedges, and sliced chillies.
Serve hot, preferably with cooked rice or gluten-free bread.
Tip: If you're not a big fan of spicy food, you can use 1 bell pepper instead of 2 chilies.