Season the chicken legs with the dry rub or seasoning salt.
Add water to the Instant Pot and insert the trivet.
Set the chicken leg quarters on the trivet, skin side up. Drop the garlic, if using, into the water.
Secure the lid and set the vent to sealing. Pressure cook on high for 12 minutes. When done, let the pressure release naturally for 5-8 minutes, then do a quick release of the remaining pressure.
Always check that the internal temperature of the chicken has reached 165°F (74°C) to ensure they are fully cooked and safe to eat. Adjustments may be necessary based on the size and quantity of chicken legs you're cooking.
Notes
If cooking the chicken from frozen, pressure cook for 15 minutes.
You can cook more than 2 pieces at a time. When adding more, stack them at odds with each other so they aren't directly on top of each other. You can fill with chicken up to the fill line, but you will need to add additional cook time if they are stacked.
You can broil the chicken to get the skin crispy, if you wish. It takes about 3-5 minutes under the broiler.
It is not necessary to use garlic. I add it to give a little bit of aromatics to the water, but it's not required.