Stir the chicken, carrots, garlic, zest, orange juice, hoisin sauce, sugar, salt, and pepper in the insert set in a 5-, 6-, or 8-quart Instant Pot until the sugar dissolves and the mixture is uniform. Lock the lid onto the cooker.
For Pressure Cook: Set the Instant Pot for Pressure Cook or Manual and set the pressure level to LOW. The valve must be closed. Set the time for 6 minutes with the Keep Warm Setting off. --OR-- For Slow Cook: Set the Instant Pot for Slow Cook and set the level to High. The valve must be open. Set the time for 2 hours with the Keep Warm setting off.
When the pot has finished cooking under pressure, use the quick- release method to bring the pressure back to normal. Whichever cooking method you’ve used, unlatch the lid and open the cooker. Whisk the water and cornstarch in a small bowl until smooth.
Press Sauté and set it for Medium, Normal or Custom 300°F. Set the time for 5 minutes.
Stir quite often while the chicken mixture comes to a simmer. Stir in the cornstarch slurry and continue cooking, stirring almost constantly, until bubbling and thickened, less than 1 minute. Turn off the heat and use hot pads or silicone baking mitts to remove the (hot!) insert to a nearby wire rack. Cool for 2 to 3 minutes before serving warm.