In a small bowl, mix sauce ingredients and set aside.
Dice chicken into 1-inch cubes. Toss in cornstarch to coat. Once fully coated, shake off any excess.
Slice onions, peppers, and basil.
In a large skillet or wok, heat oil over medium-high heat. Cook chicken for about 3-4 minutes without stirring, until brown on one side.
Flip chicken over, then add onions, pepper, garlic, ginger, and basil to the pan. Cook an additional 3-4 minutes, stirring occasionally.
Add sauce and simmer for 2 minutes, until it thickens. Add cashews.
Serve over rice.