Chuck up a 3/4” V Groove bit in a table mounted router. In the case of the nightstand the pieces are large and since they must be held on edge against the fence we used a higher shop made fence to help hold the pieces. Depending on the size of your stock pieces you may be able to use a regular table fence as we are showing here.
Clamp the fence to the table to expose enough of the bit to make a V in the edge of the plywood and cut a sample piece to check that it is centered. Make the fine adjustments with your hammer.