Preheat oven to 350 degrees.
Heat a large OVENPROOF skillet over medium-high heat. Add 1 teaspoon of olive oil to the pan then add the spinach; cook 45 seconds or until spinach starts to wilt, stirring constantly. Add the crushed red pepper flakes and minced garlic; cook, stirring constantly, for 30 seconds. Remove from the pan and set aside. Wipe pan clean.
Combine spinach, feta cheese, pine nuts, basil, and lemon juice together in a bowl, mix until well combined. Cut a horizontal slit through the thickest portion of each chicken breast half to form a pocket. Stuff half of the filling into each pocket. Seal with wooden toothpicks. Season both sides of the chicken with sea salt, freshly cracked pepper, and garlic powder, to taste.
Heat remaining 1 tablespoon of oil in pan over medium-high heat. Add chicken; cook for 3 minutes on each side or until golden brown. Add broth, scrape up any browned pieces then cover pan with a lid. Place pan into the oven. Bake for 15 minutes, or until chicken has cooked through. Remove from the oven and let the meat rest for 5 minutes before slicing and serving with the pan juices drizzled over the top. Enjoy.