In medium bowl, combine onion, grapes, and rice vinegar; set aside.
In large skillet, heat oil over medium-high heat. Add chicken and cook, stirring frequently until just cooked through, about 6-7 minutes. Season chicken with salt and pepper. Stir in chilies, fish sauce, lime juice, cilantro, and mint.
Divide rice among four serving dishes and top with chicken, cabbage, marinated onions, and grapes; sprinkle with peanuts.