Begin by setting your Instant Pot to the "Sauté" function. Once it’s hot, add the sesame oil. Carefully place the chicken thighs skin-side down in the pot. Sauté for about 5 minutes until the skin is golden brown.
While the chicken is sautéing, in a mixing bowl, whisk together the soy sauce or Tamari, water, honey, minced garlic, grated ginger, and red pepper flakes.
Once the chicken is browned, pour the sauce over the chicken thighs in the Instant Pot. Close the lid, ensuring the valve is set to the sealing position. Select the "Manual" or "Pressure Cook" setting and adjust the timer to 10 minutes.
After the cooking time is complete, allow the Instant Pot to naturally release pressure for about 5 minutes before carefully turning the valve to "venting".
In a small bowl, mix the cornstarch and 2 tablespoons of water to create a slurry. With the Instant Pot still on the "Sauté" function, pour the slurry into the pot and stir well. Allow the sauce to simmer until it thickens.
Transfer the chicken thighs to a serving dish, drizzle the sauce over the top, and garnish with sesame seeds and chopped green onions.