Preheat your oven to 375°F (190°C).
Finely chop the fresh spinach and place it in a small mixing bowl.
Add the goat cheese, Greek yogurt, and garlic powder to the spinach, stirring until the mixture is creamy and well combined.
Cut a horizontal pocket into the thickest part of the chicken breast, being careful not to cut all the way through.
Stuff the spinach mixture into the chicken pocket and secure the opening with two toothpicks.
Season both sides of the chicken breast with sea salt and black pepper.
Heat olive oil in an oven-safe skillet over medium-high heat. Sear the chicken for 3 minutes per side until a golden crust forms.
Place the asparagus spears in the skillet around the chicken and transfer the pan to the oven.
Bake for 12 to 15 minutes, or until the chicken reaches an internal temperature of 165°F.
Remove toothpicks before serving the chicken alongside the roasted asparagus.