Season the chicken breasts with Italian seasoning, paprika, salt and pepper.
Heat oil in a large skillet over medium-high heat. Add the chicken and sear until golden brown on both sides, about 4–5 minutes per side. Transfer chicken to a plate (it doesn’t need to be cooked through yet).
In the same skillet, add garlic until fragrant, about 1 minute. Stir in the chicken stock, scraping up any browned bits from the pan.
Lower heat to medium, then pour in the heavy cream. Stir in the tomatoes, Parmesan cheese, and red pepper flakes if using. Simmer for 3–4 minutes until slightly thickened.
Return chicken to the skillet, spoon sauce over the top, and simmer uncovered for 10-12 minutes, or until chicken is cooked through to an internal temperature of 165°F.
Stir in fresh basil just before serving. Serve chicken with extra sauce over pasta, rice, or mashed potatoes.