Pat the chicken breasts dry with a paper towel. Using a large, sharp knife slice the chicken breasts in half, lengthwise.
Combine the salt, garlic powder, paprika, Italian herbs, and pepper. Stir to combine. Sprinkle on both sides of the chicken breasts.
Heat a large skillet over medium high heat. Add half the oil and once hot, cook the chicken breasts on each side for 3 minutes. Remove the chicken and set aside.
Add the remaining oil to the pan and once hot, sauté the onion sfor 4 minutes. Then add the tomatoes and cook for an additional 3 minutes.
Add a little of the chicken stock to the pan to deglaze the bottom. Use a spatula to gently scrape up the bottom. Pour in the remaining stock and the Boursin cheese. Use the spatula to break up the cheese and stir it till it’s combined.
Bring the sauce to a gentle boil and reduce to a simmer. Simmer for 5 minutes then add the chicken breasts back in. Simmer for an additional 5 minutes or until the chicken breasts have reached an internal temperature of 165 degrees F on an instant read thermometer.
Remove from the heat and top with chopped parsley.