Cook pasta according to package instructions. Drain and set aside for later.
Heat oil in a large skillet over medium-high heat. Rub chicken all over with the blackened chicken seasoning. Carefully add chicken to the hot skillet and cook for 3-4 minutes on each side until done. Internal temp should be at least 165 degrees. Remove from heat.
In another large skillet over medium heat, add butter and onions. Cook for a few minutes until onions are soft. Add the garlic, basil, parsley, black pepper and cook for another minute. Slowly pour in the heavy cream while stirring. Stir in parmesan cheese until melted.
Transfer chicken to a cutting board and cut into bite size pieces.
Toss cooked pasta into the sauce and stir to combine. Sprinkle chicken on top. Serve with more fresh parmesan and a sprinkle of parsley (optional). Enjoy!