In a small bowl, mix together the Italian seasoning, salt, and pepper. Rub the seasoning mixture onto the chicken thighs, coating them evenly.
Heat the olive oil in a large skillet set over medium-high heat. Add the chicken thighs to the skillet and cook for 3 to 4 minutes on each side or until they are browned and crispy.
Reduce the heat to medium and continue to cook the chicken for 10 minutes, until it is cooked through.
Remove the chicken from the skillet and set aside.
For the Spinach
In the same skillet, melt 1 tablespoon butter over medium heat. Add the garlic and sauté for 20 seconds or until it is fragrant. Add the spinach and a pinch of salt and sauté until the spinach is wilted, about 1 minute. Remove the spinach from the skillet and set it aside.
For the Mushrooms
In the same skillet, melt 1 tablespoon butter over medium heat. Add the mushrooms and sauté until they are tender and browned. Season the mushrooms with salt and pepper to taste. Remove the mushrooms from the skillet and set them aside.
For the Gnocchi
Meanwhile, cook the gnocchi according to package directions. Drain in a colander and set aside until assembly.
In the skillet, melt 2 tablespoons butter over medium heat. Add the garlic and sauté for 20 seconds or until fragrant. Add the heavy cream and chicken broth to the skillet and bring the mixture to a simmer. Add the grated parmesan cheese and whisk until it is melted. Taste and, if necessary, season the sauce with additional salt and pepper to taste.
In the skillet with cream sauce add the cooked gnocchi and stir gently to coat the gnocchi in the sauce. Add in the cooked chicken, spinach, and mushrooms to the skillet and stir to combine.