Make Adobo Sauce: Combine Filipino soy sauce, regular soy sauce, Filipino vinegar, fish sauce and sugar in a medium mixing bowl.
Brown Chicken: Add oil to the pot and brown the chicken for 1 to 2 minutes with the skin side down first. (Instant Pot users: press sauté button) Then, remove the chicken from the pot.
Saute Aromatics: Sauté garlic and onion in the pot until fragrant and golden in color. Then, add ground black peppercorn, red chili, and bay leaves to the pot and sauté for 30 seconds.
Deglaze: Add the Sauce mixture and deglaze the pot.
Pressure Cook Chicken Adobo: Add drumsticks back into the pot and cook at high pressure for 9 minutes with an Electric Pressure Cooker, then natural release.