Is it safe to remove nasal polyps both sides through endoscopy surgery?

Yes. A well trained ENT doctor, with a thorough knowledge of the 3-dimentional anatomy of the paranasal sinuses,should be able to remove your polyps with endoscopic control. Remember, the surgeons MUST explain the potential risks associated with this surgery.
Yes. Yes, assuming you understand risks and benefits of surgery. Begin discussion with your ent.