Make sure the stainless steel insert is in your Instant Pot.
Press "saute" setting. Add butter to insert and let melt.
Place chicken thighs in Instant Pot and brown on both sides for a few minutes. The chicken does not need to be fully cooked. Just brown it a bit to add texture. Press "cancel/off" button.
In a measuring cup, whisk together ¼ cup of water, soy sauce, brown sugar, vinegar, salt and pepper. Add grated garlic cloves. Pour sauce over chicken.
Close lid of the Instant Pot, switch the valve to "sealing" position.
Press "manual" setting and adjust timer to 7 minutes. The Instant Pot will beep and start coming to pressure.
When the timer is done, the Instant Pot will beep. Press "off/cancel" button. Do not release pressure. Let the pressure release naturally. When the done, carefully open the lid.
Remove chicken onto a serving platter.
In a measuring cup, whisk together flour and water to make a slurry.
Press "saute" setting on Instant Pot, add slurry to sauce and cook until thickens. Turn off the Instant Pot.
Pour sauce over chicken and serve.
Notes
You can use cornstarch in place of flour to make the sauce gluten free. It will also make it clearer and glazy.