Heat 60g butter in a large pan over medium-high heat. Add 2 chicken breast fillets and fry for 4-5 minutes per side until golden brown and cooked through (internal temperature 74°C / 165°F). Remove and set aside. Add 2 onions (sliced) to the pan and cook over medium heat for about 5 minutes, stirring occasionally, until translucent.
In a small bowl, mix 1 tablespoon cornstarch with some of the 450ml apricot nectar until smooth, then stir in the remaining nectar. Pour into the pan with the onions. Bring to a boil over medium-high heat, stirring. Season with salt and pepper to taste. Add the 150g dried apricots and cooked chicken back to the pan. Reduce heat to medium and simmer for about 5 minutes.
Add the green pepper to the pan. Simmer over medium heat for 5 minutes. Remove from heat and stir in sour cream or crème fraîche to finish. Serve with rice.