If desired, heat taco shells according to package directions.
Melt butter in a large nonstick skillet over medium-high heat. With the chicken, ginger root, and garlic. Cook for 3 to 5 minutes, stirring frequently until the chicken is lightly browned.
Coat with soy sauce, honey, onion, and pepper flakes. Reduce heat to low, cover, and cook for 5 minutes, or until chicken is no longer pink in the center, stirring occasionally.
To serve, fill each taco shell with an adequate amount of 1/4 cup of the chicken mixture. Serve with lettuce on the side. Serve right away.