Stir together spice rub ingredients in a small bowl. Set aside.
Cut pork roast in half.
Add the two pork roast pieces to the inner pot.
Sprinkle spice mixture over the surface of the roast.
Pour the broth around the pork pieces.
Top with garlic and onion.
Close and lock the lid.
Press manual high pressure and adjust the cooking time to 90 minutes.
Let the pressure release naturally for 20 minutes.
Unlock the lid, and shred the pork before serving.
Notes
Spice blend: Feel free to adjust the seasonings to your tastes. The seasoning blend doesn't have any heat to it. If you'd like to add some heat, you can throw in some cayenne pepper along with the rest of the seasonings.