I made a front box for my Honda of 1/2" plywood that keeps shucking bolts out.
Any ideas on something better?

Plastic truck toolbox from some place like Tractor Supply? they have a bunch of different types/sizes.

nyloc nuts.

Milk crate

Premier Plastics box on Amazon. Not to big, not too small. Keeps stuff very dry. I mounted mine on the rear rack.