Wash the green mung beans and add it to the inner pot of instant pot.
Wash and chop the tomatoes to small pieces, add the chopped tomatoes also to the pot (if you want to add onions, you can also add a sliced onion to the instant pot now along with the chopped tomatoes. To make it more spicy, you can also add sliced green chilies if you wish).
Add salt and all spices to the instant pot, stir well.
Add 3 cups of water (or broth) to the pot and also add the oil, stir well again and close the instant pot with lid in sealing position.
Press manual and pressure cook in high for 5 minutes of time.
Once the cooking is done and instant pot beeps, press 'keep warm/cancel' button and wait for natural pressure release which will take another few more minutes. You may do a gradual controlled manual release of the pressure after 12 minutes of natural pressure release if needed.
Once the pressure is all released, carefully open the lid. Stir the contents and if needed for gravy, add one more cup of extra water (or as preferred) and simmer for about a minute (using the saute function). Delicious mung bean curry or green moong dal curry with tomatoes & spices is ready to be served. If you wish, you can add couple of spoons of heavy cream or coconut milk to make the curry creamy and more flavorful!
Serve the green moong dal curry or mung bean curry with a bowl of rice or serve with Indian breads like chapathi, poori, naan bread etc as you wish. You can also garnish the curry with chopped cilantro leaves or green chilies (as I used) or add an Indian style seasoning or tadka (tempering) with cumin seeds (or mustard seeds), dried broken red chilies, curry leaves etc which can be lightly fried in a tablespoon of oil in a separate pan and added to the prepared curry if you wish.