Whisk together all ingredients for marinade and add chicken. Coat chicken well in marinade and let sit for at least 15 minutes, but you could make this well in advance.
Heat grill (or grill pan) to medium-high heat. Add marinated chicken and let grill for about 7-8 minutes per side until it’s cooked through. If your chicken is really thick, it might need another few minutes. Ideally, use a meat thermometer and cook it until it hits 165 degrees in the thickest part of the chicken.
Let chicken rest for a few minutes after it comes off the grill and the slice into big chunks.
Cook soba according to directions. When the soba has 2 minutes left to cook, add edamame to the same pot to thaw them.
Drain soba and edamame and toss with rice wine vinegar, sesame oil, and chili sauce. Season with a pinch of salt or a dash of soy sauce.
Toss soba and edamame with chicken and garnish with scallions. This dish is great hot or cold.