Make the sauce: Combine oyster sauce, soy sauce, sesame oil, and cold water. Add cornstarch and mix again.
Open Instant Pot. Select the Sauté.
Add vegetable oil. Once that heats up, add in ground beef.
Add in tofu, and broccoli. Add in your sauce.
Close Instant Pot. Select manual, high pressure cooking, for 0 minutes.
When done, do a quick release and serve.