Make dry rub: Combine salt, pepper, Chinese five-spice, garlic powder, and onion powder in a small bowl. Set aside.
Make sauce: Whisk together ginger, garlic chili sauce (start with 1 teaspoon), tamari, honey, water, cider vinegar, and salt in a medium bowl. Set aside.
Place ribs in a large bowl. Sprinkle dry rub over ribs and toss to coat completely, rubbing seasoning into all sides.
Place seasoned ribs in Instant Pot in a single layer without stacking. Pour sauce over the top.
Lock lid into place and set pressure valve to “Sealing.” Select “Manual” or “Pressure Cook” on High for 25 minutes.
While ribs cook, line a large rimmed baking sheet with aluminum foil. Set aside.
When timer goes off, allow pressure to release naturally for 10 minutes, then quick release any remaining pressure. Once pin drops, carefully remove lid.
Position oven rack a few inches below the broiler element. Preheat broiler to high.
Using tongs, carefully transfer ribs to prepared baking sheet. They’ll be very tender and may want to fall apart – that’s good!
Make cornstarch slurry: Mix cornstarch with an equal amount (2 tablespoons) of hot cooking liquid from the pot in a small bowl. Stir until smooth with no lumps.
Select “Sauté” on Instant Pot at highest setting. Bring sauce to a boil, stirring frequently. Slowly add cornstarch slurry a little at a time, stirring constantly, until sauce thickens to a glossy glaze, 1-2 minutes.
Turn off Instant Pot. Transfer thickened sauce to a bowl. Brush generously over both sides of the ribs.
Broil ribs for 2-3 minutes until edges start to caramelize and darken. Flip and repeat on other side, watching carefully to prevent burning.
Remove from oven. Brush with more sauce, then sprinkle with sliced green onions and sesame seeds. Serve immediately with remaining sauce on the side.