Pain relief only. They are signs of osteoarthritis. As long as they don't hurt, there's nothing you need to do. If you do have pain then any of the many treatments for osteoarthritis would be indicated. Discuss with your pcp what treatment would be best given your medical situation.
Pain control, PT. Bouchard's nodes are an end result of degenerative arthritis of the middle knuckle of your fingers (pip joint). For unclear reasons, bone on bone damage causes more bone to be made generating these nodes. We do not have the technology to reduce their growth. Pain control and hand physical therapy are key for maximal symptom control.