Heat butter in a large skillet over medium-high heat.
Add cubed chicken breast to the pan in a single layer and brown until golden and mostly cooked through.
Remove chicken from the skillet and set aside.
Add minced garlic to the pan and sauté until fragrant.
Pour in chicken broth, scraping the bottom of the pan to release any browned bits.
Bring the liquid to a simmer, then add the dry fettuccine noodles.
Cook the pasta, stirring occasionally, until the liquid is mostly absorbed and pasta is nearly al dente.
Pour in the heavy cream and return the cooked chicken to the skillet.
Continue to heat and stir until the sauce thickens and the pasta is perfectly tender.
Stir in the grated parmesan cheese until fully melted and emulsified before serving.