Set the Instant Pot to Sauté mode. Add the ground turkey and chopped onion and cook, breaking the turkey apart as it browns, until the turkey is fully cooked through and no pink remains. Drain any excess liquid from the pot.
Add the chili seasoning and half cup of water to the turkey and onion mixture. Stir thoroughly to coat everything evenly. Turn off the Sauté function.
Drain and rinse the black beans and add them to the pot. Add the canned corn along with the liquid from the can.
Pour in the salsa, crushed tomatoes, and low sodium chicken broth. Stir everything together gently to combine.
Secure the Instant Pot lid and make sure the valve is set to Sealing. Set to High Pressure for 10 minutes. The pot will take a few minutes to come to pressure before the cook time begins.
When the 10 minutes are up allow the pressure to naturally release for 10 minutes. After 10 minutes carefully switch the valve to Venting to quick release any remaining pressure. Open the lid away from you.
Stir the chili and ladle into bowls. Top each serving with 1 tablespoon of light sour cream and 2 tablespoons of shredded cheddar cheese before serving.