Rinse rice in Instant Pot under cold water by gently scrubbing the rice with your fingertips in a circling motion. Pour out the milky water, and continue to rinse until the water is clear, then drain well. Take out and set aside.

Preheat the Instant Pot multicooker by selecting the Saute function on the keypad. When the inside pot is heated in about 1 minute, add the oil. Saute the garlic for 2 minutes till crisp. Remove the fried garlic and drain on paper towels. Set aside.

Keep saute setting, add the onions, ginger and scallion whites. Continue saute for 1 minute. Pour the fish sauce into the pot and add the chicken pieces. Scatter the rice grains over the chicken inside the pot. Pour the water (or chicken stock) into the pot (if using water, add chicken bouillon to the pot. Season with salt and ground black pepper. Do not stir. Click CANCEL to turn off Saute function.

Using a slotted spoon, remove the whole chicken pieces and transfer them to a large chopping board. Shred the chicken meat into strips. Return the shredded chicken to the pot.