I have multinodular goiter with two nodules measuring 10 mm and 11 mm on each lobe, then there are scattered ones throughout my thyroid. Biopsy?

Depends. The decision to biopsy is made between you and your treating physician. It depends on your level of comfort, what it looks like on ultrasound and whether or not it had changed from previous ultrasounds. Your choice right now is to undergo biopsy or do another ultrasound in 1 year and biopsy only if changes are seen. Both choices are reasonable.
Thyroid. If the nodules are benign by ultrasound (spongiform , isoechouc or hyperechoic) , they do not need biopsy but should be watched for growth.