I installed some old kitchen cabinets in my garage as a work and storage station recently. I'd like to install some light fixtures underneath the wall cabinets. Is it likely to be legit to run the Romex from the fixtures, straight back to the wall, then along the wall/cabinet inside corner over to a dedicated j-box? It won't be protected but there is little chance of damage to the plastic sheathing.

I'm installing a switch for the two lights on the bottom face of the wall cabinet. The Romex will extend into the cabinet interior as well.

This sound safe to you or should I place it in some sort of conduit where it is on the wall?