Melt the butter in a large skillet over medium heat. Add the chicken breasts and cook until just done — about 4–5 minutes per side. Transfer the chicken to a baking dish and cover to keep warm, leaving the pan drippings behind.
In the same skillet, add the flour to the drippings and stir until pasty and golden. Add the chicken broth, minced garlic, and red pepper flakes to the roux. Simmer for about 1 minute.
Add the cream cheese, heavy cream, tomato sauce, most of the Parmesan cheese, and oregano. Stir continuously over medium-high heat until the sauce is thick and bubbly.
Pour the sauce over the chicken in the baking dish. Sprinkle with the remaining Parmesan cheese and bake uncovered at 400°F for 10–15 minutes.
While the chicken bakes, cook your Ziti according to package directions. Drain and set aside.
Serve the chicken breasts whole or sliced over a bed of pasta. Spoon the sauce over the top, and garnish with fresh parsley or more Parmesan.