Heat the olive oil in a large pot over medium heat. Add the onion and cook for 4 minutes until it softens.
Stir in the garlic and cook for 1 minute until fragrant.
Add the chicken pieces along with the cumin, coriander, cinnamon, turmeric, salt, and black pepper. Cook for 5 minutes, stirring occasionally, until the chicken is no longer pink on the outside.
Pour in the chickpeas, diced tomatoes, and chicken broth. Bring the mixture to a boil, then reduce the heat and simmer uncovered for 15 minutes.
Add the spinach and stir until it wilts, about 2 minutes.
Remove the pot from the heat and stir in the lemon juice before serving.