Heat a large, nonstick skillet over medium-high heat and add EVOO. Add the chicken and season with salt and pepper. Cook until brown, about 5-8 minutes, breaking it up into small bits with the back of a wooden spoon as it cooks. Add the onion, garlic, piquillo peppers, raisins and paprika. Continue to cook until the onions start to get tender, about 3-4 minutes. Deglaze the pan with the sherry, stirring to get any brown bits off the bottom of the skillet. Add 1 1/2 cans of tomato sauce and cook about 5 minutes more. Turn off the heat and add the parsley, almonds and cooked rice to the pot. Stir to combine.
Pour the remaining 1/2 can of tomato sauce into an oven-safe baking dish with a touch of water for additional liquid to create a bed for the peppers to sit on. Fill each pepper up halfway with the chicken and rice filling mixture.
Top with a little manchego cheese then fill with more chicken and rice mixture, and a little more cheese on tip of that. Set in the baking dish and place the tops back on top of each pepper as a lid. Bake, uncovered, for 20-30 minutes.