Whisk together the vinegar, soy sauce, sesame oil, Swerve, peanut butter, and chili garlic sauce in a medium bowl until the sugar is dissolved.
Put the chicken breasts into a gallon-sized Ziploc bag and pour the marinade over them. Put them in the fridge, making sure the bag is as flat as possible, for two hours, turning once.
Preheat your grill to medium-high heat. Put the chicken on the grill, leaving the excess marinade in the bag to discard. Grill for 10-12 minutes, turning every 2 minutes or so, until the chicken breasts are browned and cooked through. Sprinkle with sesame seeds before serving, if desired.
Macros for this recipe are difficult to calculate because so much of the marinade is discarded. Assuming that just shy of 2 tablespoons of the marinade end up remaining on each chicken breast (likely a high estimate), the macros are as follows: 183 calories, 6 grams net carbs, 27 grams protein, 8 grams fat.
