Traditional liposuction is the most predictable and effective always in my opinion, but for smaller areas Smart Lipo can be effective. Of course, for smaller areas you may benefit from fat freezing or in some cases even Kybella.A photo is helpful! For any of these it's a brief office visit procedure.
If your chin is loose and saggy, no type of lipo will make it pretty. The best candidates have tight skin and tight fat. Laser or regular lipo will both give excellent results if your surgeon is skilled. If your surgeon is unskilled, your results will be suboptimal with either approach with the added risk of getting a skin burn with the laser.