Pat the chicken thighs dry and season both sides with salt and ground black pepper; set aside.
Combine honey, sugar, soy sauce, water (or chicken broth), and cayenne in a bowl; stir until the honey and sugar are dissolved and set the sauce aside.
Set the Instant Pot to Sauté and heat until hot. Add 1 tablespoon cooking oil, then sear the chicken thighs skin-side down first until browned on both sides; remove and leave in the pot if desired.
Add the remaining 1/2 tablespoon oil to the pot, stir in the minced garlic and sauté briefly until fragrant, about 30 seconds.
Pour the prepared honey garlic sauce over the chicken in the Instant Pot, secure the lid, select Manual/High pressure, and cook for 10 minutes.
When the cook time ends, perform a quick release. When the valve drops, carefully remove the lid, stir in the chopped parsley, and serve immediately with the sauce.