You can be in Nicaragua legally for a long
You can be in Nicaragua legally for a long period of time on a visitor visa as long as you leave from time to time and come back. You do not necessarily have to be a legal resident to stay here.
Most of people receive a three-month visa when they arrive and they usually renew it once so they can stay for another three months, but then they would have to leave Nicaragua for three days. If they just passed over to Costa Rica, the requirement there is that you be out of the country for three hours and then you can return. This rule is now changing. The Nicaraguan government is now questioning people who come here as tourists and they are starting to apply pressure for people to apply for residency. But for now, you can live in Nicaragua even if you do not have residency.