The answer depends on whether the stain is solvent based or water based. For the stain type indicated, always do a small test sample before you attempt it on your actual project.
Solvent-based stains - No, do not apply a solvent-based stain over cured TotalBoat epoxy products because the solvent-based stain can cause delamination and/or contaminate the epoxy.
Water-based stains - Yes, you can apply a water-based stain on cured TotalBoat epoxy. Be sure the stain is completely dry before applying another layer of epoxy, if desired.