Combine the sauce: in a liquid measuring cup or small bowl, add tamari, ketchup, honey, mashed garlic, Italian seasoning, and chopped parsley; stir until smooth.
Place the chicken thighs in a single layer in the Instant Pot.
Pour the sauce evenly over the chicken, making sure the honey is fully incorporated into the mixture.
Close the lid and set the valve to sealing. Cook on high pressure for 12 minutes for frozen thighs or 8 minutes for fresh thighs.
Allow the Instant Pot to naturally release pressure for 5–10 minutes, then carefully release any remaining pressure and open the lid.
Serve one thigh per person over your choice of starch and sprinkle with sesame seeds and sliced green onions.