In a food processor, process the sun dried tomatoes, garlic cloves and walnuts. While processing drizzle the olive oil, and keep processing until you get a relatively smooth paste. If you don't own a food processor, you can chop everything with a knife or with a pestle and mortar.
With a sharp knife, open up the chicken breast, to get a thinner and bigger surface. Make sure the meat stays in one piece. When finished flattening the breast, make some diagonal cuts on the side with no skin. Season the meat with salt, pepper and chilli.
When finished, rub some of the paste inside the cuts, also make sure you rub some of it under the skin. Roll the breast into a tight roll and tie it with thread, or secure it with tooth picks. Repeat the whole thing with the other breast. Put the breasts in a bowl, cover it and leave in the fridge over night.
Heat the oven to medium high heat. Put the chicken breasts in a cooking bag or wrap them in an aluminium foil. Bake them in the oven for 40 minutes. Those are great in a sandwich.