Begin by cooking the pasta according to package instructions in a large pot of salted boiling water. Drain and set aside, reserving a little pasta water for later.
In a large skillet, heat the olive oil over medium-high heat. Add the chicken strips and season with salt and pepper. Cook until browned and cooked through, about 5-7 minutes. Remove the chicken from the skillet and set aside.
In the same skillet, add the butter. Once melted, add the chopped onion, sliced mushrooms, and bell pepper. Sauté for about 5 minutes, or until the vegetables are tender.
Stir in the minced garlic and cook for an additional minute until fragrant.
Pour in the chicken broth and scrape the bottom of the skillet to release any browned bits. Allow the broth to simmer for about 2-3 minutes.
Reduce the heat to low and stir in the heavy cream, Parmesan cheese, Italian seasoning, and optional crushed red pepper flakes. Mix well and let it simmer for another 3-4 minutes until the sauce thickens slightly.
Return the cooked chicken to the skillet, tossing it in the sauce to coat. If the sauce is too thick, add a splash of reserved pasta water to reach your desired consistency.
Add the cooked pasta to the skillet and gently toss everything together until well combined. Adjust the seasoning with salt and pepper to taste.
Remove from heat and garnish with fresh parsley before serving. Enjoy your delicious pasta dish!