Pat the chicken breasts dry with paper towels. Season generously with salt, pepper, garlic powder, and paprika. Heat olive oil in a large skillet over medium-high heat. Add the chicken breasts and sear for 5-7 minutes per side until golden brown and cooked through (internal temperature of 165°F/74°C). Remove from skillet and set aside, tenting with foil to keep warm.

Fill a large pot with salted water and bring to a boil. Add the rotini and cook according to package directions (about 8-10 minutes) until al dente. Reserve 1 cup of pasta water, then drain the pasta and set aside. Toss with a little olive oil to prevent sticking if needed.

In the same skillet used for the chicken, melt the butter over medium heat. Add minced garlic and cook for 1-2 minutes until fragrant, being careful not to burn it. Pour in the heavy cream and bring to a simmer. Stir in the grated Parmesan cheese until melted and smooth. Season with salt, pepper, and a pinch of red pepper flakes. If the sauce is too thick, add reserved pasta water until desired consistency is reached.

Add the cooked rotini to the sauce and toss to coat. Return the chicken to the skillet, nestling it into the pasta and sauce. Simmer for a few minutes to meld flavors. Garnish with fresh parsley and serve hot.