Heat olive oil in a large skillet over medium-high heat. Season the chicken pieces with salt and pepper, then add to the skillet. Cook for 5-7 minutes until golden brown and cooked through. Remove the chicken from the pan and set aside.

In the same skillet, add the diced onion and saute for 3 minutes until softened. Add the minced garlic and cook for 1 additional minute until fragrant.

Stir in the uncooked rice, toasting it slightly for 1-2 minutes. Pour in the chicken broth and bring the mixture to a simmer.

Reduce the heat to low, cover the skillet tightly with a lid, and simmer for 15 minutes, or until the liquid is absorbed and the rice is tender.

Uncover the skillet and stir in the fresh baby spinach, allowing it to wilt for 1-2 minutes in the residual heat.

Stir the cooked chicken back into the skillet along with the grated Parmesan cheese. Mix until the cheese is melted and creamy.

Serve immediately, garnished with extra grated Parmesan cheese and freshly cracked black pepper.