Pat chicken dry and lightly pound. Season with 1 tsp salt, 0.5 tsp pepper, paprika, and Italian seasoning.
Heat 2 tbsp olive oil in a large skillet over medium-high. Sear chicken 4–5 minutes per side until browned and cooked through. Transfer to a plate.
Reduce heat to medium. Melt 2 tbsp butter in the skillet. Stir in 2 tsp minced garlic and red pepper flakes; cook 30 seconds until fragrant.
Add broth and lemon juice, scraping up browned bits. Simmer 2–3 minutes to reduce slightly. Whisk in remaining 2 tbsp butter, then return chicken and any juices. Spoon sauce over and sprinkle with 1 tbsp parsley. Keep warm on low.
Meanwhile, warm a second skillet over medium heat. Add 1 tbsp olive oil and 1 tbsp butter.
Sauté 1 tsp minced garlic for 20 seconds. Add riced cauliflower; season with remaining 0.5 tsp salt and 0.25 tsp pepper. Cook, stirring, 5–7 minutes until tender.
Stir in heavy cream and Parmesan until melted and creamy. Fold in remaining 1 tbsp parsley and adjust seasoning.
Spoon Parmesan cauliflower rice into bowls. Top with chicken and drizzle with the garlic butter pan sauce.