Preheat oven to 350°F. Combine quinoa and stock in a saucepan. Bring to a boil and reduce heat to simmer for 15 minutes. Cut the tops off of the bell peppers, remove the seeds. Chop the tops of the peppers (dice and keep to add to filling). Trim peppers bottoms (if necessary) so that they will stand up. Heat the olive oil over medium high heat in a large sauce pan. Saute the garlic and onions. Add and peppers and curry powder. Saute 2-3 minutes. Add the chicken, salt and pepper to the pan. Cook until the meat is browned. Add the tomatoes. Stir to combine. Cook until most of the liquid is absorbed (5 minutes). Add the cooked quinoa to the meat mixture. Stir thoroughly. Fill each pepper with the mixture. Cook in preheated oven for 30 minutes. After 25 minutes, top each pepper with cheese. Cook five more minutes until cheese begins to brown.