Cook the pappardelle pasta according to package instructions until al dente. Drain and set aside, reserving 1/2 cup of pasta water.
In a large skillet, heat olive oil over medium-high heat. Add the chicken pieces, season with salt and pepper, and cook until browned and cooked through, about 6-8 minutes. Remove the chicken from the skillet and set aside.
In the same skillet, add the sliced mushrooms and cook until they are golden brown, about 4-5 minutes. Add the minced garlic and sauté for an additional minute until fragrant.
Pour in the chicken broth and bring to a simmer, scraping up any browned bits from the bottom of the skillet.
Reduce the heat to low and stir in the heavy cream and Parmesan cheese. Cook for 2-3 minutes until the sauce thickens slightly.
Return the cooked chicken to the skillet and add the drained pappardelle. Toss everything together, adding reserved pasta water as needed to reach desired sauce consistency.
Serve immediately, garnished with fresh parsley.