Alaska Fish Fertilizer (5-1-1) is a good example of a high Nitrogen nute that is reasonably priced and available just about "everywhere". Regular Bat Guano (Mexican Freetail, 10-3-1) is another good choice, but may be a little harder to find.
Bloodmeal has lots of Nitrogen, but it's slower acting and might be a little tricky to "dose out"!