Sealant to increase Water-Resistance of SLS print
SLS prints from nylon are somewhat porous. This means, that they will let a stabilizer soak into the outer surface to some degree.

What kind of stabilizer is needed is depending somewhat on the properties you want, but generally I believe these might be useable depending on the viscosity:


2-component resins could be used, but they are usually very viscous. Their viscosity, however, is dependent on the exact type and mixture and could be altered by temperature.
1-component (air-hardening) resins or resin lacquers can be thinned to achieve a solution into which the item is then dunked and dripped off. How much thinner is adviseable depends on the exact material
Nitrocellulose lacquer, like it is used in guitar building, is extremely fluid and could be used for treatment via dunking.
PU lacquer could be used too.