Preheat oven to 350°F.
Cut bell peppers in half and scoop out the seeds and membranes. In a large pot, add water, a pinch of salt and peppers. On medium high heat, cook peppers for about 5 minutes or until slightly softened. Remove from heat and drain water. Coat a square baking dish with cooking spray. Prepare couscous according to package instructions and set aside. In a baking dish, place pepper halves standing up and set aside. Drain roasted peppers and pour into a blender. Pulse to chop well. Heat oil in a skillet over medium heat. Add chicken, onion, fennel seeds and chickpeas. Cook, stirring frequently, for 5 minutes or until vegetables are softened. Remove from heat and stir in cherry tomatoes, tomato paste, oregano, roasted peppers and sour cream.
Using a fork, fluff the cooked couscous then add to cooked chicken and vegetable mixture. Stir gently to blend. Add salt and pepper to taste.
Fill each pepper half to the top.
Bake 20-25 minutes or until peppers are slightly browned.
Serve and top with fresh basil leaves, and crumbled feta cheese.