There are several 18th century-type references to desires for sexual activity and reactions to these references and an implied sexual encounter (off-screen) between a married couple. Also some wink-wink, nudge-nudge among the delegates regarding the above. As best I recall, the closest thing to nudity was Martha Jefferson's decolletage.
References to "whores" and "the French Disease" may raise some eyebrows.
It should be noted that in 2003 the Fairfax County VA school board banned 1776 over Jefferson's declaration of his yearning for his wife. If this is a point of concern for you, view the movie before showing it to your children.