Bring a pot of water to a boil and season generously with salt. Cook the fettuccine for 1 minute less than the packet instructions. Drain and reserve ½–1 cup of pasta water.
Slice the chicken into two fillets and place in a bowl. Add the onion powder, garlic powder, smoked paprika, salt, and pepper. Mix well.
Place a pan over medium-high heat and add the olive oil. Sear the chicken for 2 ½–3 minutes per side, or until the internal temperature reaches 74°C (165°F). Remove, rest for 5 minutes, and thinly slice.
Place the same pan, or a clean pan, over medium heat. Add the butter and garlic and sauté for 2 minutes, until the butter foams and the garlic is fragrant but not browned.
Increase the heat to medium-high, add the cream, and mix well. Season to taste and bring to a boil. Reduce the heat to low and simmer for 5–6 minutes, until thickened and slightly reduced. Add the Parmigiano Reggiano and nutmeg and gently mix to combine.
Add the drained pasta, mix to coat, and cook for 1 minute. Adjust the consistency with the reserved pasta water if needed. Remove from the heat.
Serve the Alfredo pasta in a bowl, laying the sliced chicken on top. Garnish with parsley and Parmigiano Reggiano. Dig in.