Prep the Chicken: Place the chicken breasts on a cutting board, cover with plastic wrap to avoid splatter, and gently pound them to an even thickness (about 3/4-inch). Slice each breast in half for thinner pieces, or use pre-sliced filets. Season with salt and pepper.
Cook the Chicken: Heat oil in a large skillet over medium heat. Once hot, swirl the oil to coat the pan and add the chicken. Cook for 5-7 minutes per side until golden brown and cooked through. Transfer to a clean plate and cover to keep warm.
Prepare the Sauce: While the chicken cooks, chop the spinach and artichokes into smaller pieces. Mince the garlic. Once the chicken is done, remove it from the skillet and set aside. Add butter and garlic to the skillet, sautéing for about 1 minute until fragrant.
Make the Sauce: Pour chicken broth into the skillet, scraping the browned bits from the pan. Cut the cream cheese into chunks and add it along with the sour cream. Whisk the mixture until smooth and the cream cheese is fully melted. Stir in the milk, and continue whisking until smooth.
Finish the Sauce: Add the grated parmesan, red pepper flakes, and freshly ground pepper. Stir for a few more minutes. Gradually add the spinach, stirring until wilted. Then, mix in the chopped artichoke hearts.
Combine and Serve: Return the chicken to the skillet, spoon the creamy spinach artichoke sauce over the chicken, and serve hot.