In a large skillet or wok, heat the vegetable oil over medium heat. Add the sliced chicken and cook until browned, about 5-7 minutes. Remove the chicken and set aside.
In the same skillet, add the onion, garlic, and ginger. Sauté for 2-3 minutes until the onion is translucent.
Stir in the Panang curry paste and cook for another minute until fragrant.
Pour in the coconut milk, fish sauce, and brown sugar. Stir well to combine.
Return the chicken to the skillet and bring the mixture to a simmer. Cook for 10 minutes, allowing the flavors to meld.
Add the red bell pepper and green beans, cooking for an additional 5 minutes until the vegetables are tender.
Remove from heat and stir in the lime juice.
Serve hot, garnished with fresh basil leaves over steamed rice or noodles.