When the Instant Pot is hot, saute the chicken, onions, bell peppers, and garlic together in the Instant Pot. Add the chilli powder, cumin, salt, pepper, and crushed red peppers.
Mix in the tomato paste so that the chicken and veggies are covered while it sautés. Sauté for 1-2 minutes.
Turn off the Instant Pot and add the chicken stock and can/tin of diced tomatoes. Stir the soup to ensure there is no tomato paste stuck to the bottom of the Instant Pot.
Close the lid and turn the pressure valve to the sealing position. Cook the soup on high pressure using the "pressure cook" or "manual" setting for 1 minute. Let the pressure release on its own naturally. This will take 10-15 minutes. If you are in rush you can release the pressure doing a controlled quick release.
Turn the Instant Pot off and remove the lid. Skim the top of the soup with a ladle to remove any impurities floating on the top.
Serve the soup still hot, topped with sour cream, avocados, jalapenos, and cilantro/coriander.
The majority of the carbs come from the diced tomato, onion and peppers. To reduce the carbs further, you may reduce these vegetables, but this may also reduce the flavours so add extra spices.