I have spondylolysis and grade 2 spondylolithesis. starting physio this week. on naproxen 375 twice day.is manual traction from chiropractor ok?

maybe: As long as it does not cause pain down the leg it is fine.

Yes, but,,,,,: Yes, but it won't work. Manual traction cannot exert enough force to provide any benefit for lumbar spine issues.

Yes traction is ok : as one part of your treatment but the main one should be working on your core strength to help better stabilize your spine while maintaining good flexibility and cardiovascular conditioning.