Cook gnocchi according to package directions, reserve 1/4 cup cooking liquid.
Meanwhile, heat oil in large skillet over medium heat.
Add onions and cook until softened, about 5 minutes. Add chicken and cook, crumbling it with a spoon, about 5 to 7 minutes.
Add the mushrooms, garlic, salt, and pepper and cook, tossing frequently, about 3 minutes. Add spinach, toss until the spinach wilts. Add the drained gnocchi, the reserved cooking liquid, and the Parmesan and toss.
Divide among individual bowls and sprinkle with additional Parmesan.