It is believed that he did say something similar that was later changed by William Hull .
From William Hull 's memoirs, that was written decades after the Revolution. By then, a country and government that were already abusing the people's hard-won liberties had been established. But in 1782, just six years after Nathan Hale's death, an article appeared anonymously in the Boston Chronicle. Evidence suggests that Hull was its author. Here he quotes Captain Hale's last words as, "'I am so satisfied with the cause in which I have engaged, that my only regret is that I have not more lives than one to offer in its service.'"
Obviously, the shorter version packs a greater punch, but it also changes "cause" to "country." Nathan Hale was no nationalist. He gave his life for the cause of liberty, not for a collection of state governments that hardly existed at the time .