The H-1B1 visa category for residents of Chile or Singapore can only be issued for one year at a time. However, the H-1B1 visa status is renewable indefinitely, provided that you are able to demonstrate that you do not intend to remain or work permanently in the United States (i.e., no green card).
Keep in mind that you may be asked to prove "residence" in your home country of Chile or Singapore at any time.
Your H-1B1 Visa can be renewed either with U.S. Citizenship and Immigration Services (USCIS) or at a U.S. consulate abroad, provided that you are able to demonstrate that you do not intend to remain or work permanently in the U.S.