Well, there are plenty to choose from in this speech where the Chorus calls upon the audience to suspend their disbelief once again and use their imagination to call up the sights of the ships leaving England full of soldiers and travelling to France to begin Henry's military campaign.
Consider the following description of the seige at Harfleur:
Work, work your thoughts, and therein see a siege:
Behold the ordnance on their carriages,
With fatal mouths gaping on girded Harfleur.
Consider how the "ordnance" on the "carriages" are compared to "fatal mouths" that turn towards Harfleur as the English army starts its siege of this French city. The description of these mouths that "gape" at Harfleur certainly help to exaggerate the might of Henry's army and its power.
Also, consider how the Chorus describes Henry's fleet:
O, do but think
You stand upon the ravage and behold
A city on the inconstant billows dancing;
For so appears this fleet majestical...
Note how the vast numbers of this fleet, and therefore the military might of England, is exaggerated by its comparison to a "city on the inconstant billows dancing." The Chorus is keen to present the fleet as being powerful, mighty and numerous, and the figurative language that is used in this speech certainly helps to exaggerate the military might of Henry and the forces that he has under his control.
I hope that these two examples help you. Now go back and re-read this speech and see if you can identify any more examples of figurative langauge. Good luck!