ENT first. Start with a good ENT in your area that has experience treating singers. The ENT can determine the correct diagnosis and treatment, which often includes working with a speech therapist to change any vocal habits that may have led to the problem. Voice rest and lots of fluids are a must!
Not surgery. Vocal cord nodules are usually caused by inflammation of the vocal cords. It can be difficult to determine what causes this inflammation. It could be vocal abuse, acid reflux, post nasal drip, allergies, etc. Treating the underlying problem is the key. Surgery is not the answer.