Sauté the onions. In your 6qt Instant Pot/ pressure cooker set to sauté on medium heat, add oil, ghee and onions. Keep an eye on the onions, stir frequently. You want the onions to be a golden colour. Add in all the spices and sauté 2 minutes until fragrant.
Coat the chicken in the spices. Add the chicken to the Instant Pot, allow the chicken to be coated in the spices, 2-3 minutes (chicken should be a nice yellow colour from the turmeric). Once the chicken is coated in the spices, add the potatoes and give a good stir. Cook for 1-2 minutes⏤we're just coating them in the spices.
Toss in the mung beans & tomatoes. Add in your mung beans, garlic and diced tomatoes. Stir, and cook for 2-3 minutes.
Season. Add the stock cube and water to the soup, stir everything. Turn off the sauté function.
Set the Instant Pot. Cover and seal the Instant Pot. Set the Instant Pot to the bean/chilli function and time for 15 minutes. Once the time is finished, you can choose to do a quick release or a low release. I prefer a 5-minute slow release. I'll leave the choice up to you.
Release the pressure. Remove the lid. If the stew looks a bit dry, add ½ cup of water. (don't worry, it won't affect the taste too much.) Take out the chicken thighs allow cooling slightly on a plate. Remove the meat from the bones.
Final Touches. As the chicken cools, add the spinach and bell peppers to the stew. Stir and cover for 5 minutes to allow the final ingredients to cook and flavours to marry each other. After 5 minutes, add the chicken meat back into the stew. You may need to adjust the salt at this point.
Serve. Ladle the stew in a shallow bowl and serve with sumac onions, cilantro, and lime.