Prep your ingredients before you start cooking - once the recipe is started, it goes quite fast. Be sure to cut the veggies into pieces that are bite-size (make sure that the broccoli is cut quite small) so they cook at a similar rate.
Add the sauce ingredients to a medium bowl and whisk together.
Add 1 tablespoon of the olive oil and the ground chicken to a large skillet over medium-high heat. Cook the chicken, breaking it up with your spoon as you go along, until it's no longer pink and fully cooked through (about 6-8 minutes), stirring occasionally. Transfer the chicken to a plate or bowl.
Add the rest of the oil to the skillet, followed by the onion. Cook it for about a minute.
If the pan is looking dry, add a small splash more oil, then add in the rest of the veggies (peas, peppers, broccoli, carrots) and cook for 3-4 minutes or until they're tender-crisp. If you prefer them to be softer, cook them for a little longer.
Add the cashews to the skillet as well as the cooked chicken. Pour the sauce into the skillet. Let it bubble until thickened (less than a minute), stirring constantly so everything is coated. Take the stir fry off the heat and serve immediately.