Place the onion slices in the bottom of a 6 quart or 8 quart instant pot. Then set the trivet over the top of the onions.
Add 1 ½ cups of water to the instant pot.
In a small bowl combine the spices: paprika, garlic powder, onion powder, dried thyme, salt and black pepper.
Pat the chicken dry with paper towels.
Place the lemon halves inside the cavity of the whole chicken.
Rub the olive oil all over the chicken.
Sprinkle the spices under the skin and all over the top of the chicken.
Place the chicken, breast side up, on top of the trivet in the instant pot.
Place the lid on the instant pot and set the valve to sealing.
Set the instant pot on high pressure for 25 minutes or 5 minutes per pound of chicken.
Let the pressure cooker do a natural release, takes about 15-20 minutes.
Once the pin has dropped, carefully remove the lid.
Check and make sure the internal temperature of the chicken has reached 160°F in the thickest part of the thigh.
Remove the chicken and place on a cutting board or platter.
Let the chicken rest for 10 minutes before carving.
If you'd like a more crispy skin you can set the chicken on a sheet pan and broil it on high for 2-4 minutes. You can also use the air fryer lid for the Instant Pot and set it on 400°F for 4-5 minutes.