Cut your chicken breast into bite-size pieces. Season with salt and pepper and transfer them to a bowl.
Add the cornstarch and toss to coat evenly.
In a small bowl add the soy sauce, vegetable stock, sugar, garlic, brown sugar, hoisin sauce and sesame oil. Mix to combine. Set aside until ready to use.
In a large skillet heat 1 tablespoon of oil over medium-high heat. Add half of the chicken pieces in a single layer. Cook until the chicken is lightly browned on one side, for about 1-2 minutes. Flip to the other side and cook for an additional 1-2 minutes.
Remove the chicken to a clean plate. Repeat with the remaining chicken.
Return the first batch of chicken to the skillet.
Add the green onion, the cashews, the soy sauce mixture and rice vinegar into the skillet.
Cook for another 2 minutes until the sauce thickens.
Sprinkle spring onion and sesame seeds over the chicken and serve with rice, noodles and veggies.