Cook gnocchi according to the directions on the box. Drain and set aside.
Heat a cast iron skillet (or frying pan). Spray with no-stick cooking spray and add the garlic. Saute the garlic for 1 minute, making sure the garlic doesn't burn.
Add the chicken broth and the spinach. Cook for a few minutes, until the spinach is cooked.
Add the half and half, stir. Bring to a simmer.
Mix the cornstarch with 1-2 tablespoons of chicken broth or water. Add to the pan. Simmer (while stirring) until the sauce thickens and reduces somewhat.
Add the gnocchi and chicken. Serve!