Season the chicken: Pat chicken dry.
In a bowl, toss with Cajun seasoning, smoked paprika, red pepper flakes, salt, and black pepper until evenly coated.
Preheat the pan: Heat a large skillet over medium-high. Add olive oil and 1 tablespoon butter.
Sear the chicken: Add chicken in a single layer. Cook 3–4 minutes per side until browned and cooked through.
Work in batches if needed to avoid steaming. Transfer to a plate.
Build the scampi base: Reduce heat to medium. Add 1 tablespoon butter and the garlic.
Sauté 30–45 seconds until fragrant, not browned.
Deglaze: Pour in the white wine (or broth), scraping up browned bits. Simmer 2–3 minutes to reduce slightly.
Finish the sauce: Stir in lemon zest, lemon juice, and remaining 2 tablespoons butter. Whisk until glossy.
Taste and adjust salt and heat levels.
Bring it together: Return chicken and any juices to the pan. Toss to coat. If serving with pasta, add cooked pasta plus a splash of pasta water and toss with Parmesan until silky.
Garnish and serve: Sprinkle with parsley.
Serve immediately over pasta, rice, or with crusty bread. Add extra lemon wedges and Parmesan if you like.