Add the soy sauce, water, rice vinegar, brown sugar, garlic, and ginger to the Instant Pot and whisk to combine. 

Next, add the chicken and toss to combine. 

Attach the lid and ensure the valve is in the “sealing” position.

Set the Instant Pot to the Pressure Cook Manual for 7 minutes. 

When the Instant Pot has finished, release the pressure manually by switching the valve to the “venting” position. Be careful, it will steam and splatter. 

In a small bowl, whisk together the cornstarch and 1 tablespoon of water.

Add the slurry to the Instant Pot and mix to combine. 

(Optional) The sauce will thicken slightly when you add the slurry but if you want a thicker glaze, turn the Instant Pot to the Saute function and cook it for 1-2 minutes, or until the sauce is your desired consistency. 

Turn the Instant Pot off and add the broccoli on top of the chicken (do not stir it together). Attach the lid and allow the broccoli to steam for 5 minutes. 

Serve this teriyaki chicken and broccoli over rice, garnished with green onion and sesame seeds. Enjoy immediately.