Add the ground chicken and onions. Brown 7-8 minutes. Use a Mix 'n' Chop or wooden spatula to keep the chicken nice and ground. Your mixture should still be a little juicy from the onions at this point. If not, add back a tablespoon of water.
Add the lime juice, chipotle powder, cumin, garlic (or garlic powder) and salt, and cook 1-2 minutes until mixed well and juice is mostly cooked down.
Test the meat mixture, and add more salt to taste if necessary. Add cayenne pepper 1/8 tsp. at a time if you want a little more heat.