Visas are only required by the following countries. Afghanistan, Albania, Algeria, Angola, Armenia, Bangladesh, Bosnia-Herzegovina, China, Congo (Democratic), Congo(Republic), Cuba, East Timor, Eritrea, Ethiopia, Ghana, Haiti, India, Indonesia, Iran, Iraq, Jordan, Laos, Lebanon, Liberia, Libya, Mali, Mongolia, Mozambique, Nepal, Nigeria, North Korea, Pakistan, Palestine, Sierra Leone, Somalia, Sri Lanka, Sudan, Syria, Vietnam and Yemen.
Everyone else gets 30 days or more at the border or airport. You may have to pay for a visa on arrival or US$10 for a tourist card.
Nicaragua visa requirements