In a small bowl, whisk together Italian seasoning, salt, black pepper, garlic powder, and chili powder. Coat chicken breasts thoroughly with the seasoning mixture and set aside.

Fill a large stockpot with water, add salt, and bring to a boil. Cook fettuccine according to package instructions, reserve 1½ cups of pasta water before draining.

In a cast-iron skillet, heat olive oil over medium heat. Add seasoned chicken and cook for approximately 3 minutes per side until golden brown. Remove chicken and cover to keep warm.

In the same skillet, lower heat and add butter. Once melted, add minced garlic and cook until fragrant. Pour in reserved pasta water and chicken broth, scraping the bottom.

Stir in remaining seasonings and allow sauce to simmer for about 5 minutes. Mix in Parmesan cheese until melted, then add drained fettuccine, and toss to coat.

Garnish with additional Parmesan and sliced green onions before serving warm.