Melt the coconut oil in a large sauté pan over medium heat. Add the diced pepper and celery, and sauté until tender, around 5 minutes.
Add the chicken, onion powder, and garlic powder. Stir well and season with salt and pepper, to taste. Cook for 2-3 minutes, or until the chicken is heated through.
Add the hot sauce and sauté while stirring for another minute or two, until the sauce is heated through and everything is well coated. Remove from heat and stir in the sliced green onions.
To serve, fill Bibb lettuce cups with a few tablespoons of the chicken mixture and enjoy!