To prepare vegetables, dice 1 medium onion, 3 stalks celery, 3 cloves garlic and shred 2 carrots.
Cook 1 pound of chicken and cube in to small pieces.
Heat olive oil in a large pot over medium heat. Cook onion, celery, garlic, and carrots in the hot oil until onion is translucent, about 5 minutes.
Stir in cubed chicken and chicken broth; bring to a simmer.
Stir gnocchi into the simmering soup and cook until they begin to float, 3 to 4 minutes.
Stir in spinach; cook until wilted, about 3 additional minutes.
Optional for thickening: Whisk 1 tablespoon cornstarch into 2 tablespoons cold water until smooth. Stir cornstarch mixture and milk into simmering soup.
Cook until soup thickens slightly, about 5 minutes. Season to taste with salt and black pepper.