Pat dry chicken thighs and trim any fat. Season with salt and pepper.
Choose the sauté function on your Instant Pot. Add the olive oil. Once heated through, carefully place in batches of the boneless chicken thighs (3-4 at a time). Sauté the chicken thighs and flip once a slightly crispy edge appears. Continue browning the other side of the chicken thighs. Repeat steps until all thighs have been browned and remove to a plate. Browning should take about 2 minutes on each side.
With the instant pot still on the sauté function, add in remaining olive oil, then garlic and onion. Sauté and stir for just a minute until softened. Turn off sauté mode.
Add the red wine, chicken brown and brown sugar to the instant pot and whisk until blended. Place the browned chicken thighs back into the instant pot in a single layer.
Seal the lid and make sure the vent is set to closed. Cook on high pressure for for 10 minutes. After the 10 minutes of pressure cooking is finished, carefully open the vent and manually release the pressure.
Once the pressure indicator has moved to done, turn the instant pot to off and remove the lid. Remove the chicken thighs to a plate and keep warm.
Return the instant pot to sauté and whisk in 1 Tablespoon of corn starch. Bring to a boil until the sauce becomes thick (approximately 5 minutes). Once the sauce is thick, spoon it over the chicken, turn off the instant pot and serve. Enjoy!