Cut the spring onions into pieces and peel and dice the mango. Set aside.
Heat 1 tablespoon peanut oil in a pan over medium-high heat. Add the diced chicken breast and cook, stirring frequently, until the internal temperature reaches 74°C (165°F). Season with salt and pepper, then remove from the pan and set aside.
In the same pan, add the spring onions and sauté over medium-high heat for 1-2 minutes.
Add the green beans and sauté for 1 minute.
Add the ground coriander and sauté for 1 minute.
Pour in the coconut milk and bring to a boil, stirring to combine. Season with salt, pepper, and sambal oelek to taste.
Cover the pan, reduce heat to medium-low, and simmer for 4 minutes.
Add the diced mango and simmer for 4 minutes.
Return the chicken to the pan and heat through for 1-2 minutes. Taste and adjust seasoning if necessary.