Mix the spices together for the rub. Remove 2 Tablespoons of the mix and set aside for later.

Rub all sides of the pork roast chunks generously with the spice rub. Set meat aside.

Cut the onion into 8 pieces (cut in half, then cut each half into 4 pieces). Put the onion into the inner cooking pot of the pressure cooker.

Pour the can of pop (or water/broth) into the the pot over the onion*.

Set the pork chunks on top of the onions. Sprinkle the brown sugar over the pork.

Place the lid on and lock into place. Set the steam release knob to the sealing position.

Press the Pressure Cook/Manual Button (or use dial) and then the +/- button (or dial) to choose 65 minutes. High Pressure.

After the cooking time has finished, let the pot sit undisturbed for 15 minutes. Then turn the steam release knob to the Venting position (or push button) to manually Quick Release the remaining pressure/steam.

When the pin in the lid drops down, open it and remove the meat to a large bowl. Use a slotted spoon to get the onions out and add to the meat. Use two forks to shred the meat.

Sprinkle the reserved spice rub and ½ tsp salt into the meat. Mix well. Taste and add more salt and/or brown sugar, if desired.

Use a large spoon (or a fat separator) to skim off the fat from the cooking liquid that is still in the pot. Then add ½ - 1 cup of the liquid to the meat and mix in. You can add more of the liquid to the meat if you like it more moist.

Serve on buns, or over rice or potatoes, or in tortillas.