Can a few lung nodule disappear / cannot see in cxr over a year if you undergo treatment or something?

Good question. For your doctor. These are multiple reasons for lung nodules and your question can be answered more accurately by the doctor who has examined you.
May be. If suspected benign modules followed up on x ray disappear on repeated x rays then observation is justified.
Yes. "lung nodule/s" is a radiographic finding and not a diagnosis. The presence of nodules does not indicate cancer and the vast majority of nodule are in fact benign (not cancer). They can be inflammation, infection, scar, and numerous other possibilities. As such, yes, many nodules to shrink, "resolve", and/or disappear.