Inertial confinement doesnt produce a “stable reaction” it is pulsed by it’s nature, think of it in the same way as a single cylinder internal combustion engine, persiodic explosions which are harnessed to do useful work. So no the laser energy is required every single time to detonate the fuel pellet.

NIF isnt really interested in fusion for power production, it’s a weapons research facility that occasionally puts out puff pieces to pretend it has civilian applications.