Finely mince the garlic, grate the ginger, and thinly slice the green onions.
In a small bowl, whisk together the coconut aminos, rice vinegar, and arrowroot powder until the powder is fully dissolved.
Heat a large non-stick skillet over medium-high heat and add 2 tablespoons of the chicken broth to prevent sticking.
Add the ground chicken breast to the skillet, seasoning with sea salt and black pepper, and cook until browned and crumbled.
Stir in the garlic, ginger, and the white parts of the green onions, sautéing for 1 minute until fragrant.
Add the diced water chestnuts, cooked brown rice, and the remaining chicken broth to the skillet, stirring to combine.
Pour the coconut aminos mixture over the chicken and rice, tossing constantly for 1-2 minutes until the sauce thickens and coats everything evenly.
Remove from heat and stir in the remaining green onion tops.
Gently separate the butter lettuce leaves and wash them in cold water, patting them dry with a paper towel.
Spoon the savory chicken and rice mixture into the center of each lettuce leaf and serve immediately.