Since usually by the time you can discern the details, chances are pretty good you could care less whether you're dealing with an alligator or a crocodile...and Nicaragua has both.
But to satisfy any curiosity you might have - before you come across one of these - there's a lot of good information to be had in the link below. As pointed out in the link, there's a surprisingly lot of difference between alligators and crocodiles. The best thing to do, though, is to concentrate on how to avoid either:
https://tinyurl.com/mr43u544