Sear the Chicken: Heat vegetable oil in a large pot over medium heat. Add the chicken pieces, season with salt and black pepper, and cook until golden brown. Remove from the pot and set aside.
Sauté the Aromatics: In the same pot, add garlic, ginger, bell pepper, and onion. Stir in red curry paste and cook for 1-2 minutes until fragrant.
Create the Broth: Pour in chicken broth and coconut milk. Stir in fish sauce and brown sugar. Let it simmer for 10 minutes, allowing the flavors to meld.
Simmer to Perfection: Return the cooked chicken to the pot and let it cook through for another 5 minutes.
Cook the Noodles: Add rice noodles to the soup and simmer until tender, about 3-5 minutes.
Finish & Serve: Remove from heat and stir in lime juice. Garnish with fresh cilantro, basil, and green onions before serving.