Well, first of all, he could fight pirates and stuff in his own time. Then if he time travels, it might be interesting if he goes to a 20th-century fencing match and surprises some people by showing off his 18th-century skills. . .And then just about any fight scene can become an opportunity for a sword to come into play, which would be especially interesting if some of the fights occur in exotic locales linked to the plot's historical backdrop. Also, in addition to knowing fencing, Nathaniel might know some of the hand-to-hand fighting styles of his time, which could also be interesting. Maybe his fencing master taught him fighting in general.
Designing a pamphlet's a lot of work! I've done a few of those for martial arts schools.
plot bunnies are starting multiply....