Season the chicken. Pat the chicken dry. Season all over with 1 teaspoon salt and 1/2 teaspoon pepper. You can add a pinch of Italian seasoning here too.
Brown the chicken. Heat the olive oil in a large deep skillet or Dutch oven over medium-high heat.
Add the chicken in a single layer and cook 4–6 minutes, stirring once or twice, until golden and just cooked through. Transfer to a plate and tent with foil.
Sauté the aromatics. Reduce heat to medium. Add the butter.
Once melted, stir in the onion and a pinch of salt. Cook 3–4 minutes until soft. Add the garlic and cook 30 seconds until fragrant.
Toast the rice. Stir in the rinsed rice, sun-dried tomatoes, Italian seasoning, and red pepper flakes.
Cook 1–2 minutes, stirring, to coat the rice in the flavorful fat. This step helps the rice cook up fluffy and flavorful.
Add broth and simmer. Pour in the chicken broth and scrape up any browned bits from the bottom. Bring to a gentle boil, then reduce to a low simmer.
Cover and cook 15–18 minutes, until the rice is tender and most liquid is absorbed. Stir once halfway if needed to prevent sticking.
Make it creamy. Uncover and stir in the heavy cream. Return the chicken and any juices to the pan.
Simmer on low 2–3 minutes to warm through and slightly thicken.
Add cheese and greens. Turn off the heat. Stir in the Parmesan until melted and smooth. Fold in the spinach until just wilted, 1–2 minutes.
Add lemon juice, then taste and adjust with salt and pepper.
Finish and serve. Let the pan rest 3–5 minutes so the rice sets and thickens. Garnish with chopped basil or parsley. Serve warm.