Cut the beef and broccoli into bite sized pieces.
Mix the sauce ingredients, except the cornstarch, in a small bowl. Add 1 tbsp of the sauce to the beef. Stir to coat and set aside to marinate.
Set the Instant Pot to saute. Add the cooking oil. When hot, add the broccoli and saute, stirring occasionally, for about 5 minutes. Remove the broccoli from the pot. Cancel saute mode.
Add the beef to the Instant Pot, along with 1/2 cup chicken broth. Lock the lid and turn the vent to sealing. Using the pressure cook button, set the Instant Pot to 4 minutes.
Meanwhile, add the cornstarch to the remaining sauce and stir it until smooth.
When the time is up, do a manual release of pressure and remove the lid.
Press saute mode again and add the broccoli back to the pot.
Pour the sauce over the beef and broccoli. Stir well and allow the sauce to thicken for about 3 minutes. Turn off the Instant Pot. Serve over rice, if desired.