In a small bowl, toss the chicken pieces with the arrowroot powder, salt, and pepper.
Heat the oil in a large skillet over medium high. Once the oil is hot and shiny, add the chicken mixture and sauté for 4 minutes, just until lightly browned. Add the bell pepper, broccoli, and green onions. Continue sautéing until the chicken is cooked through and the vegetables are crisp-tender, about 5 additional minutes. Stir in the cashews and cook for 30 additional seconds.
While the chicken and vegetables are cooking, prepare the sauce. In a small bowl or large measuring cup, stir together the tamari, rice vinegar, 2 tablespoons honey, ginger, garlic, and 1/4 teaspoon red pepper flakes. Taste and add additional honey and/or red pepper flakes as desired (I added an additional 1/4 teaspoon red pepper flakes). Pour the sauce over the skillet and toss to coat. Enjoy immediately with brown rice.