In a large bowl, add the chicken cubes and cornstarch and stir until the chicken is well coated.
In a saucepan over high heat, add the olive oil, once hot add the chicken, brown 3-4 minutes on each side. Cook until the chicken is golden.
Remove the chicken pieces from the pan and set aside.
In the same pot over medium-high heat add the peanut butter, soy sauce, sesame oil, garlic and chicken broth. Stir to combine all the ingredients and have a homogeneous sauce. Bring to a boil, reduce the heat to low and add the chicken cubes.
Continue cooking for 3 to 5 minutes or until peanut sauce has thickened and chicken is cooked through and no longer pink inside.
Remove from heat and sprinkle with green onions.