Turn the heat on the wok to medium. Add the oil and give it a minute to heat up.
Add cashews and cook for 3-4 minutes until they take on a dark golden color.
Remove from the wok with a slotted spoon and store them on some paper towels to absorb the oil.
Turn the heat up to high. Throw in garlic and onion and fry until lightly browned. Be careful as the garlic easily burns.
Add the chicken and cook until it's white on its whole surface. No need to brown it.
Add white part of green onions as well as chili slices. Stir-fry for another minute or two.
Add the sauce and cook until it reduces down to a thicker, syrupy consistency. This should take no longer than two to three minutes.
Add the green part of the sliced green onion and the cashews. Mix well.