In a bowl, combine salt and pepper (to taste), 1 teaspoon garlic powder, 1 teaspoon onion powder, and 1/2 teaspoon smoked paprika. Add the chicken pieces and toss until fully coated.

Heat 2 tablespoons olive oil in a large skillet over medium-high heat until shimmering. Add the chicken in a single layer (cook in batches if needed to avoid overcrowding). Cook until golden and no longer pink in the center, about 5–7 minutes, turning as needed. Transfer the chicken to a plate and set aside.

Reduce heat to medium. Add 2 tablespoons of the butter to the same skillet. When melted, add the minced garlic and sauté about 1 minute, until fragrant (do not let it brown).

Pour in 1 cup chicken broth and scrape the bottom of the skillet with a spatula to loosen browned bits. Bring to a boil, then let reduce for 2–3 minutes.

Lower the heat to medium (or medium-low) and stir in 1 cup heavy cream, the juice and zest of 1 lemon, 1 teaspoon dried oregano, and 1/4 teaspoon red pepper flakes. Simmer gently about 5 minutes, until the sauce begins to thicken.

Stir in the remaining 2 tablespoons butter and 2 cups roughly chopped fresh spinach. Cook, stirring, until the butter melts and the spinach wilts (about 30–60 seconds).

Return the cooked chicken and any accumulated juices to the skillet. Stir to coat the chicken with the sauce and simmer 2–3 minutes more, until the chicken is heated through and the sauce reaches your desired consistency. Taste and adjust salt and pepper if needed.

Remove from heat and, if desired, sprinkle with freshly grated Parmesan cheese before serving.