The US Postal service has a number of different service levels.
Global Express Guaranteed takes 1-3 days
Express Mail International 6 days
Priority Mail International 6-10 days
First Class Mail 6-20 days
Most people estimate that a Frist Class letter to Nicaragua would take about 10 days
Next day delivery
First Class Mail is delivered in three to five days.
first class mail is delivered in 3 to 5 days
First class mail is delivered in three to five days.
First class mail delivery takes 3 to 5 days.
First class mail delivery takes 3 to 5 days.
First Class Mail is delivered in three to five days.
First class mail is delivered in 3 to 5 days
First Class Mail is delivered in three to five days.
First class mail is delivered in 3 to 5 days
It takes 3-5 business days for first class mail to be delivered.
1 to 2 weeks or more