Which of the following services are nail technicians authorized to perform?

Nail technicians are specifically trained and authorized to perform services that focus on the health and aesthetics of the nails. This includes nail enhancements, such as acrylics or gels, as well as repairs to damaged nails. This aligns with their scope of practice, which is primarily concerned with the nails and surrounding skin rather than broader beauty treatments or esthetics.

The other options involve services outside the typical duties of a nail technician. Facials and chemical skin treatments require a different level of training and licensing, often associated with estheticians rather than nail technicians. The option that limits services to only pedicures and manicures does not encompass the full range of capabilities that nail technicians are trained to provide, such as nail enhancements and repairs. Lastly, stating "all beauty treatments" incorrectly implies that nail technicians can perform any service within a salon environment, which is not accurate, as their expertise is specialized and regulated.