Season the chicken pieces with salt, pepper, and paprika evenly on both sides.
Turn the Instant Pot to SAUTE, on high. Add oil, and allow the oil to heat for about a minute.
Working in batches, add chicken to the Instant Pot and saute until brown on both sides. This takes about 6-8 minutes, depending on the thickness of your chicken pieces.
Once all chicken pieces are browned evenly on both sides, add the soy sauce, sugar, vinegar, chicken stock or broth, garlic, bay leaves, onions, and 1/2 teaspoon pepper. Stir ingredients together.
Follow the manufacturer instructions for properly placing the pressure cooker lid on and setting it to seal. Set to PRESSURE COOK (or MANUAL, depending on your IP) on high for 9 minutes. After the pressure builds, the IP count down from 9 minutes. At the end, when it beeps, carefully use tongs or a thick kitchen towel to turn to Quick Release. Once the float valve is completely down and all steam has been released (mine takes about 2-3 minutes for quick release; your time may vary), carefully unlock and open lid.
Press the SAUTE setting and bring the remaining sauce to a boil, then allow it to reduce until it turns a nice dark brown color. This takes about 15 minutes.
Once the sauce is reduced to your liking, remove bay leaf and hit CANCEL. Transfer chicken to a serving plate and garnish with scallions. Serve inmediately.