Place the onion inside the chicken. Pat the outside dry with a paper towel.
Mix together the salt, garlic powder, and smoked paprika in a small bowl. Sprinkle the mixture over the outside of the chicken, patting gently to help the mixture adhere if necessary.
Add the chicken stock to a 6-quart electric pressure cooker.
Add the steamer insert, then place the chicken, breast-side up, in the pressure cooker.
Secure the lid, select the manual setting, and set it to high pressure for 30 minutes.
When the pressure cooker timer is done, allow the pressure to naturally release for 15 minutes, then quick release (if necessary) and remove the lid.
Remove and allow the chicken to rest, 10-15 minutes, before serving.
Note that at this point the skin will not be crispy. If you prefer just the meat, remove the skin and serve as is. If you prefer crispy skin, carefully place the chicken on a foil lined sheet pan. Place under the broiler, and broil 5-8 minutes, until the skin in browned and crispy.