Changes or biopsy
Lung nodules that are small and not worrisome looking(as in spiculated edges, growth, large size, newly developed, etc.
..) can be observed over 3-6 months with another ct scan
for comparison. If no change then likely benign. If something is growing or larger than 2cm or ugly looking by a radiologist then it could b. Malignant. Biopsy
is the way to know. If it is too small biopsy may not possible.