I had an enlarged thyroid which was also overactive and ended up as a "multinodular goitre". A variety of tests, including needle biopsy, were inconclusive. It seems that it's very hard to know if a thyroid nodule is malignant without actually removing it. I ended up having a total thyroidectomy, because it was so enlarged, not because of nodules. Despite being covered with nodules (one of the junior docs showed me a photo she'd taken after it was removed!), none were cancerous.
I think thyroid nodules are pretty common, and in most cases need no treatment. However, I agree that we need to be pro-active with our own health - ask questions, research on reputable websites etc. If I had listened to the endocrinologist I went to, and hadn't asked GP for referral to surgeon, I could have been strangled by my enlarged thyroid!