Bring a large pot of salted water to a boil and cook the pasta al dente according to package directions. Reserve 1 cup of pasta water, then drain the pasta. Do not rinse the pasta.
Toss the chicken breast with olive oil, oregano, paprika, garlic powder, dried sage, and red pepper flakes. Heat a deep skillet over medium-high heat and sear the chicken for 8-10 minutes, flipping halfway through until it reaches 160-165°F. Remove the cooked chicken.
Melt butter in the same pan and add fresh garlic, cooking until fragrant. Whisk in flour to form a paste, then pour in the chicken broth while scraping up brown bits.
Add milk and heavy cream, whisking to thicken the sauce for 2-3 minutes. Stir in parmesan cheese, salt, and pepper until melted.
Toss the cooked pasta in the sauce, adding reserved pasta water as needed to reach your desired consistency.
Slice the chicken and serve on top of the pasta. Garnish with red pepper flakes, shaved parmesan, or parsley.