Preheat oven to 350 degrees F and spray a 9x13 baking dish, set aside. In a 12" skillet, heat oil and combine shredded chicken breast, onion and bell pepper (and/or chili peppers, optional). Stir in taco seasoning, reserving 1 tsp for the cheese mixture. Saute until chicken is browned and onions are translucent. In a small sauce pot, over very low heat, combine plain Greek yogurt, cottage cheese, 1/3 cup Monterrey jack cheese and 1 tsp taco seasoning. Stir until cheese melts. I used my immersion blender to make this into a smoother sauce, this is optional. Heat tortillas until soft. In each tortilla, place a spoonful (each) of the cheese and meat mixtures. Roll tortilla and place in the prepared baking dish. Repeat for all 12 enchiladas. Top with any remaining meat and cheese mixture, Enchilada Sauceand remaining shredded cheese. Bake for about 30 minutes or until cheese is melted and bubbly.