In a medium saucepan, add at least one teaspoon of salt and bring to a boil. Add the pasta and cook until done per the package's directions. While the pasta is boiling start cooking the chicken.
Cut the chicken breasts in half lengthwise. Then place the chicken between parchment paper and pound with the flat side of a meat mallet until they are a 1/4 inch thick. Sprinkle each side with salt and pepper. Continue to pound the remaining chicken breasts.
Heat a large cast iron skillet over medium heat. Once you feel the heat radiating from the skillet, add the oil and swirl it around until the surface of the skillet is covered. Add several pieces of chicken. Don't overcrowd the chicken. Cook for about 3 minutes per side. You want the chicken to be lightly brown before you flip it over.
Continue to cook the remaining chicken. Cut one piece of chicken to ensure that it is cooked through.
Thinly slice the chicken.
Drain the pasta. Return to the pot or a pretty serving bowl. Pour the pesto over the pasta. Add the chicken and sun-dried tomatoes. Toss and serve.
Recipe by Nourishing Simplicity at https://nourishingsimplicity.org/2019/04/pesto-pasta-with-pan-seared-chicken.html