Season the thinly pounded chicken breasts on both sides with salt and pepper. In a large skillet over medium-high heat, add the olive oil. Once shimmering, add the chicken breasts and cook for 4-5 minutes per side, until golden brown and cooked through. Remove from the skillet and set aside.

Reduce the heat to medium. Add the butter to the same skillet. Once melted, add the minced garlic and cook for about 30 seconds until fragrant, being careful not to let it burn.

Pour in the chicken broth and lemon juice, scraping up any browned bits from the bottom of the pan. Bring to a simmer, then add the uncooked fettuccine, ensuring it's submerged. Cook for 8-10 minutes, stirring occasionally, until al dente.

Stir in the heavy cream and grated Parmesan cheese until the sauce is smooth. Slice the cooked chicken and return it to the pan. Garnish with fresh parsley, toss to combine, and serve immediately.