Whisk together the chicken broth 1 Tbsp of sriracha, ground black pepper, salt and the one tablespoon of rice vinegar. Set aside
Place the chicken breasts into the Instant Pot® and pour the mixed sauce over the top.
Close the pot and make sure the steam valve is set to “seal”. Press the “Manual” Button and set the timer for 6 minutes. When the timer goes off, allow the pressure to naturally release for 10 minutes and then push open the steam valve to release the remaining pressure. Open the lid and remove the chicken, chopping it up or shredding it with two forks. Add the chicken back into the sauce mix in the Instant Pot®.
Make extra sauce by mixing the mayonnaise with the remaining sriracha, rice vinegar and sugar. Blend into the chicken in the pot.
Serve the chicken over rice along with the purple cabbage and tomatoes.