Turn instant pot on sauté mode (medium heat). Add olive oil, onions, and garlic and sauté for 2 minutes. Add curry powder, ginger, and cayenne and continue sautéing for 2 minutes, stirring and scraping continuously.
Add cashews and 1/2 of the coconut milk. Stir and cook for 1 minute. Turn off Instant Pot. Using gloves, carefully pour contents of the Instant Pot into a blender and blend until smooth. Return blended mixture to the Instant Pot.
Add remaining coconut milk and water as needed to reach your desired consistency. (This may not be needed if you prefer a thicker curry.)
Add chickpeas. Place the lid on the Instant Pot, seal it, and set to Manual mode, high pressure for 5 minutes. Quick release when the cycle is complete.
Add spinach and cashewmilk yogurt. Stir until spinach is wilted and the yogurt is thoroughly incorporated. Taste and add salt as needed.
Serve over basmati rice or with naan bread. Top with a lime wedge and a sprinkle of fresh cilantro.