In a medium pot, add the chicken, garlic, lime zest, salt, red pepper flakes (if using), and 1 cup coconut milk. Stir to combine, then bring to a gentle simmer, cover, and simmer for 12-15 minutes, or until the chicken is cooked through (breasts may take longer - if not cooked through, flip them over, cover, and simmer 3-5 more minutes).
Transfer the chicken to a cutting board. Add bell peppers to the pot and simmer uncovered for 5–10 minutes to reduce slightly and concentrate flavor.
Shred up the chicken and return to the pot. Add lime juice and more salt, if needed. It should be a little tangy and well-seasoned.
Meanwhile, add the coconut lime sauce ingredients to a jar with a tight-fitting lid and shake vigorously to combine. If the nut butter isn’t mixing, use a fork to mash it up or it can also help to warm up the mixture in the microwave and shake again.
Toss herb salad together in a bowl. Pour about half of the coconut lime sauce (a scant ½ cup) over top along with ¼ teaspoon salt and toss to coat. If you have extra cilantro or scallions, chop them up and stir it into the chicken.
Add the saucy chicken/peppers into warm tortillas or over warm rice along with the herb slaw, and avocado. Drizzle some of the remaining sauce over top along with sriracha/chili oil if you want a little kick. Top everything with a squeeze of lime, if you’d like.