Press the Sauté button on the Instant Pot® and heat oil. Add pork and cook, crumbling well, until browned, about 10 minutes. Add hoisin sauce and stir to coat pork, then add onion and cook until tender, about 5 minutes. Add garlic, soy sauce, Chinese five-spice, and pepper and cook until fragrant, about 1 minute.
Add broth and coleslaw mix to pot and stir well. Press the Cancel button, close lid, set steam release to Sealing, press the Manual button, and set time to 8 minutes.
When the timer beeps, quick-release the pressure.
Serve hot with wonton strips and scallions for garnish.