Before you begin, chop/mince your vegetables and rinse the rice in a fine strainer until the water runs clear. You want to remove all the starch so the rice doesn't stick.
Select the sauté function on your Instant Pot or Pressure Cooker (I used my Ninja Foodi). When hot, add butter and oil, onion, and carrot. Saute for 2 minutes.
Add rice, garlic, and corn. Saute for an additional minute. Turn the pressure cooker OFF.
Stir the salt into 1½ cups of chicken broth and pour over the rice. Deglaze the bottom of the pot, if necessary.
Stir enough water into the remaining broth to equal one cup. Whisk in tomato paste, chili powder, and Tajin until the tomato paste dissolves. Pour the sauce over the rice but do not mix in. Top with the chopped tomatoes, then lock the lid and set the vent to seal. Select high pressure (pressure cook) and set the timer to 4 minutes.
When the time is up, release the pressure and do a natural pressure release (NPR) for 10 minutes. Release pressure by turning the valve to vent. Mix rice, then fluff with a fork before serving.