In a 4- to 6-quart slow cooker, place the chicken, onion, garlic, chicken broth, coconut aminos, rice vinegar, almond milk, mushrooms, ginger, and black pepper.
Cover and cook on LOW for 4 hours.
Remove the chicken from the slow cooker and slice the chicken into pieces. Prepare your noodles according to package instructions or use spiralized zucchini noodles.
Add the chicken and noodles to the slow cooker, cover, and let sit for 15 minutes.