Whisk together all of the ingredients in a small bowl for 2-3 minutes or until smooth. Add extra water if needed to make a thin, pourable sauce. Set aside.
Chicken:
Cut the chicken into bite sized pieces. Sprinkle with salt and pepper.
Heat a tablespoon of the oil in a large skillet over medium-high heat. Cook half of the chicken pieces for 6-8 minutes or until golden brown and cooked through. (Internal temp of 165°.) Transfer to a plate and repeat with the rest of the chicken.
Return the first batch of cooked chicken to the skillet and turn the heat down to medium low. Add the sauce and stir until the chicken is evenly coated and the sauce is heated through. If it gets too thick, add more water.
You can serve the chicken as is, or over a bed of white rice. If desired, garnish with green onions and sesame seeds.
Notes
To save time, I like to prepare the sauce while the chicken cooks.
Leftover peanut butter chicken can be stored in an airtight container in the refrigerator for 3-4 days.