Assuming Karl hits as a Cat 3 storm, Laguna Verde (which as best I can tell by radar is taking a direct or right front quadrant hit) should come through okay. Mexico is a pretty good nuclear plant operator, and nuke power plants are designed to handle more than a Cat 3.

I worked at Turkey Point nuclear plant when Cat 5 Andrew hit (the plant was in the eyewall but thankfully in the left front quadrant). We shut the plant down in advance of the storm to reduce the heat being generated by the reactore core (which makes it easier to keep cool). The safety related equipment that keep the nuclear core cooled in an emergency handled the wind and rain without much difficulty. The NON-safety related equipment (that actually makes the electricity) was not so fortunate and suffered quite a bit of damage. One Turkey Point unit restarted one month after the storm, the second (which also needed to be refueled) took two months. The major storm damage impact was to communications and other support equipment but I hope Laguna Verde learned from our lessons and has more robust systems.

The other post-Andrew impact was that most of the Turkey Point plant staff was effectively homeless and personnel from other plants had to come help us do the repairs since many of us were trying to get our own houses in order. Hopefully the damage to the neighboring communities from the Cat. 3 Karl won't be as bad as our staff experienced in Andrew.

If Laguna Verde takes a right front quadrant hit storm surge could be the most dangerous phenomenon (no big surprise). Nuclear plants on the ocean typically are built at an elevation above any expected storm surge but wind-driven waves can reach good heights. The Andrew storm surge at Turkey Point was relatively low. I fear Laguna Verde may not be so fortunate.