In a large heavy-bottomed saucepan or stock pot, heat the oil over medium-high heat.
Add the onion and cook until translucent, about 3 minutes.
Add the ground chicken, cumin, fennel seeds, oregano, chili powder, salt and pepper.
Cook stirring frequently, until the chicken is cooked through and no pink remains.
While the chicken cooks, julienne the spinach leaves. Set aside.
Stir the flour into the chicken mixture, making sure flour is fully blended in.
Add the chicken stock, beans, and corn.
Bring mixture to a simmer, and simmer for 45 minutes or until the liquid has reduced by about half and the chili has thickened. At this time, add the spinach and stir to combine.
Simmer for another 5 minutes.
Serve hot