Start by turning your Instant Pot to the sauté mode. Add 1 tablespoon of olive oil and 1 tablespoon of unsalted butter to the pot. Once the butter has melted, add the minced garlic, chopped onion, and chopped green bell pepper. Sauté for about 3-4 minutes until the vegetables are soft and fragrant.
To the sautéed vegetables, add the whole kernel corn, black beans, taco seasoning, salt, and black pepper. Stir well to combine all the ingredients.
Next, add the uncooked quinoa, water or vegetable stock, and the can of diced tomatoes (with their juices) to the pot. Mix everything together, ensuring the quinoa is submerged in the liquid.
Seal the Instant Pot lid, ensuring the valve is set to sealing. Set the Instant Pot to high pressure for 1 minute. Once the cooking time is complete, allow for a natural release for about 10 minutes before switching the valve to venting to release any remaining pressure.
Once the pressure has been fully released, carefully open the lid. Using a fork, fluff the quinoa and mix it with the other ingredients.
Serve your Instant Pot Mexican Quinoa in bowls and top with fresh avocado, shredded cheese, and chopped red onion. Enjoy this tasty, wholesome meal!