Set InstantPot to sauté and heat oil. Add the cumin seeds, and bring them to a sizzle. Add onion and ginger, and sauté until onion softens and wilts, about 5 minutes.
Add chicken, turmeric, cayenne, salt, and cinnamon, and mix well. Stir in spinach.
Press cancel (turns off sauté mode). Lock on the lid and set to manual pressure for 5 minutes.
When cooking time is up, allow the pressure to release naturally for 10 minutes. (At that point, if the pressure isn't fully released, you can quick-release it.)
Open the lid and stir in lemon juice.
This will be heavy on liquid, so serve with rice, naan, or some other starchy food to sop up the liquid.
