Turn the Instant Pot to saute and add the butter and onions.
Cook just until onions are translucent, stirring often.
Add the rice, garlic, thyme, salt, and pepper and cook for 2-3 minutes, stirring often, until the edges of the rice are just translucent -- watch the garlic so it doesn't burn.
Add the chicken broth to pot and scrape the bottom well to remove any bits that may be stuck on.
Turn the Instant Pot off, and with the vent in the venting position, put the lid on. Turn the valve to sealing, select Manual or Pressure Cook for 5 minutes. The Instant Pot will take about 5 minutes to build pressure and begin counting down.
When the cook time is over, turn the Instant Pot off and let the pressure release naturally for at least 10 minutes. Open the vent, then remove the lid.
Stir in Parmesan cheese, season to taste and any toppings as desired.